PSCS Wiki

Exchange 2007

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Exchange 2007 You can link VPOP3 to Exchange Server, so that Exchange Server sends outgoing mail through VPOP3 and VPOP3 sends any incoming mail directly to Exchange Server. You should first of all set up VPOP3 to send and receive Internet email as normal.

Setting up VPOP3 to work with Exchange 2003

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Setting up VPOP3 to work with Exchange 2003 The instructions below are for Exchange Server 2003. For other versions of Exchange see here. You can link VPOP3 to Exchange Server, so that Exchange Server sends outgoing mail through VPOP3 and VPOP3 sends any incoming mail directly to Exchange Server.

How To Allow Mail Relay Through VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2025-05-21T07:57:18+00:00

How To Allow Mail Relay Through VPOP3 If you are allowing remote access into VPOP3 to collect mail then you may also want those remote users to be able to send their outgoing mail through VPOP3 as well. This is more complex than allowing users to collect mail, because, by default, SMTP connections are not authenticated. This means that when someone tries to send a message through VPOP3, VPOP3 doesn't know who that user is. This can cause a problem if unauthorised users try to send mail through…

Incoming SMTP Feed

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Incoming SMTP Feed An incoming SMTP feed is where incoming mail is sent directly to your mail server without going through your ISP's POP3 mail server on the way. Advantages An incoming SMTP feed has several advantages over going via a POP3 mailbox:

Using VPOP3 with Microsoft Exchange Server

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Using VPOP3 with Microsoft Exchange Server You can link VPOP3 to Exchange Server, so that Exchange Server sends outgoing mail through VPOP3 and VPOP3 sends any incoming mail directly to Exchange Server. You should first of all set up VPOP3 to send and receive Internet email as described in the online help.

Outlook/Windows Messaging reports "No transport provider is available"

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Outlook/Windows Messaging reports "No transport provider is available" If Outlook or Windows Messaging reports No transport provider is available when trying to connect to VPOP3, it can mean several things. (This must be a contender for “the world's most meaningless error message

Sender Policy Framework / SPF

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sender Policy Framework / SPF SPF is a system used to tell mail servers which IP addresses can send mail from which domains. It is designed to reduce 'spoofing' of email addresses. For instance, if you receive an email message from your bank, your mail software can check that it came from an IP address authorised to send mail from your bank, and treat the message with suspicion if it didn't come from an authorised IP address.

550/553 Not Permitted error from BT Internet's mail servers

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

550/553 Not Permitted error from BT Internet's mail servers BT Internet's mail servers only allow messages to be sent from 'approved' email addresses. If you try to send messages from other addresses BT's mail servers may return a '550 Not Permitted' error, a '553' error, or may silently discard the message depending on what their server feels like doing today.

Setting up an iPhone/iPad/iPod Touch

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Setting up an iPhone/iPad/iPod Touch To set up an iPhone to access VPOP3's mail, you first of all need to configure VPOP3 to allow access by remote users (unless you will only be using the iPhone in the office, connected via WiFi to the office LAN). Adding the mail account to your iPhone/iPad

Sending mail through your Gmail account

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sending mail through your Gmail account According to Google, the settings for sending mail through Gmail are: Outgoing Mail (SMTP) Server - requires TLS or SSL: smtp.gmail.com (use authentication) Use Authentication: Yes Port for TLS/STARTTLS: 587 Port for SSL: 465

Using VPOP3 Spam Filtering with LAN Forwarding

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Using VPOP3 Spam Filtering with LAN Forwarding When using the VPOP3 Spam filter with LAN forwarding you need to be aware a bit of how it works. The spam filter will only quarantine messages which are going to a VPOP3 user. This is because that user needs to be able to log into VPOP3 to be able to view their quarantined messages.

How to create a Mail Sender

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to create a Mail Sender In VPOP3 a Mail Sender tells VPOP3 how to send mail out to another mail server, usually for sending mail across the Internet. To create a mail sender, go to the VPOP3 Settings, then Mail Connectors. In the Mail Senders section on the left, choose

How to make VPOP3 re-download POP3 messages from the ISP

Anonymous (anonymous@undisclosed.example.com) — 2026-04-06T17:57:00+00:00

How to make VPOP3 re-download POP3 messages from the ISP If you have the VPOP3 Mail Collector setting Leave Mail On Server enabled, then VPOP3 will leave your messages on the ISP POP3 server for the specified number of days after downloading it. If, during this time, you want to make VPOP3 download those messages again, then you can do so.

Outgoing Mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Outgoing Mail * Create a Mail Sender * Route MX Sent (Direct) Outbound Mail Through Your ISP's Relay Server * ISP needs SSL connection * ISP needs you to connect on port 587 * ISP needs SMTP Authentication * ISP Needs POP3 Before SMTP Authentication * Limit size of sent mail * Require SMTP Authentication when users send mail to VPOP3 * Sending different users' mail through different ISP relay accounts * Restricting number of messages sent (per hour etc) * Restricting numbe…

VPOP3 - POP3 Client Problem

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 - POP3 Client Problem These errors occur whilst VPOP3 is communicating with your ISP's POP3 mail server to retrieve your mail. The server connection was closed unexpectedly If the message text is Error with Pop3 Client (XXXX (YY)) The server connection was closed unexpectedly

Sending mail from different email addresses or domains

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sending mail from different email addresses or domains VPOP3 does not (by default) place any restrictions on which email addresses or domains you can send mail from. However, there may be external restrictions on which email addresses/domains you can send from. For instance, if you send mail through your ISP's mail server, they may only allow you to send mail from specific addresses, or the domain you send mail from may have a sender policy defined, such as

VPOP3 - SMTP Client Problem

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 - SMTP Client Problem These errors occur whilst VPOP3 is communicating with your ISP's SMTP mail server to send your mail. If the message text is: Error with SMTP Client (XXXX (YY)) The server connection was closed unexpectedly Then this means that the the connection between VPOP3 and your ISP's SMTP mail server was closed when VPOP3 did not expect it to be. This can be caused by the network connection failing or a bug in the ISP's mail server which drops the connection in abnormal circ…

Incoming Mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Incoming Mail Incoming mail is configured through Mail Collectors (on Mail Connectors -> Mail Collectors) * Create a Mail Collector * Delete a Mail Collector or Connection * Handling mail for multiple incoming domains * Custom filtering incoming mail

Not Working As Expected

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Not Working As Expected This is the page to come to if you think you've set something up correctly but it isn't doing what you think it should be doing. If you're getting an error message or some other concrete indication that something has actually 'gone wrong' then the

Require SMTP Authentication

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Require SMTP Authentication There are some situations where VPOP3 needs to know who is sending mail. This may be if you have VPOP3 configured to behave differently depending on who is sending messages - eg if you have different message size limits depending on the sender, or if you have message monitoring configured for certain users, or you don't want certain people to be able to send mail at all.

Route MX Sent (Direct) Outbound Mail Through Your ISP

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Route MX Sent (Direct) Outbound Mail Through Your ISP Some mail providers (for example Hotmail, AOL and GMail) will reject mail sent from servers running on dynamic IP addresses. It is possible to route such mail through your ISP's relay server whilst still sending most mail direct to the recipient server using MX

Forwarded Emails Not Arriving

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Forwarded Emails Not Arriving If you are having problems having VPOP3 forward incoming messages to an external address, but sending messages directly to that address works OK, and forwarding internal messages to that address works OK, then the problem may be the SMTP return address which VPOP3 is using.

Backscatter

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Backscatter In email, “backscatter” is the term used if you send bounce messages back to spam messages. As most spam messages use forged email addresses, then the bounce messages will go to an innocent person, who will find them very annoying. Stopping VPOP3 from sending Backscatter

Handling mail for multiple incoming domains

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Handling mail for multiple incoming domains VPOP3 can easily handle mail for several incoming domains. Exactly how you do it depends on the exact situation. All domains are 'aliases' If the domains are aliases of each other, for instance, you have 'mycompany.com' and 'mycompany.org', both of which are the same, so each address at mycompany.com also exists at mycompany.org, and the emails go to the same people regardless of which domain is used, then you simply configure the domains in the ma…

The ISP needs POP3 before SMTP authentication

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

The ISP needs POP3 before SMTP authentication Some ISPs (especially in Germany) require you to log on to collect your POP3 mail before they will allow you to send any mail through their SMTP relay servers. VPOP3 actually connects to the POP3 server and SMTP server at the same time, so usually it will not have successfully logged onto the ISP's POP3 server before it tries to start sending mail.

How to Obtain Error Logs

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to Obtain Error Logs As part of diagnosing a support issue our support team may ask you to send them various log files. This page explains how to obtain the right files at the right time. How Logging Works Under its default settings VPOP3 logs a minimal amount of information about what it is doing to various files in the main VPOP3 directory. When investigating a support issue it is often the case that we will need you to switch on logging to extra files or increase the level of detail be…

How to Obtain Message Headers

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to Obtain Message Headers Most people are familiar with mail headers such as From:, To:, Subject: etc. but there are many more which most people never see. Quite often we need to see the full internet mail headers from an e-mail that is causing problems. This article explains how to get hold of them in some of the more common e-mail clients.

Accepting Incoming SMTP through a router

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Accepting Incoming SMTP through a router If your ISP is providing you with an SMTP mail feed (incoming SMTP) and you have VPOP3 connecting to the ISP through a router then you will probably need to modify the router configuration to allow this. Most routers' default configuration will only allow outbound connections (ie connections from the local network out to the Internet). If you need to accept incoming SMTP mail, then you need to tell the router to allow inbound connections on port 25 for …

How to tell VPOP3 that some users in the local domain are not to be handled by VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to tell VPOP3 that some users in the local domain are not to be handled by VPOP3 In some situations you will have a situation where most of your users are handled by VPOP3, but several users will collect their mail directly from a separate POP3 account on your ISP, even though they may have an email address on the same domain as other users.

Mail Not Downloading From ISP

Anonymous (anonymous@undisclosed.example.com) — 2026-04-06T17:59:47+00:00

Mail Not Downloading From ISP This normally happens because you have told VPOP3 to Leave Messages On Server (on the Mail Connectors -> Mail Collectors -> (name) -> POP3 General tab). If you do this, VPOP3 will leave messages on the ISP's mail server for several days, and remember that it has already downloaded them. Then, the next time it connects it will see that there are some messages waiting, but it may find that it has already downloaded them, so it won't download them again.

RBL Checking not working in VPOP3 Enterprise

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

RBL Checking not working in VPOP3 Enterprise VPOP3 Enterprise has an RBL checking feature which is configured in the VPOP3 Settings at Services -> SMTP Server -> SPAM Reduction -> Realtime Blacklist Rules If it does not seem to be working properly, there are a few reasons why the RBL feature may not work.

Restricting the number of recipients sent to

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Restricting the number of recipients sent to Some ISPs set restrictions on the number of recipients that you are allowed to send in a certain time period, eg 50 messages per hour, or the number of recipients that you are allowed to send per message or per connection.

Seeing where a message came from

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Seeing where a message came from Sometimes you need to check to see where a message really came from. The 'From:' email address is easily forged, so that cannot be relied upon. The first thing you have to do is to get the full message headers. These may look daunting, but are very useful for problem diagnosis.

Setup steps for multiple POP3 accounts at the ISP

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Setup steps for multiple POP3 accounts at the ISP * Set up all the local users you need in the 'Users' page in the VPOP3 settings. The usernames & passwords do not have to have any relation to the ISP's accounts. These are the details which the users will put in their email clients (eg Outlook) to collect their mail from VPOP3.

SMTP Relay Protection in VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

SMTP Relay Protection in VPOP3 SMTP Relay Protection should be used on ALL SMTP mail servers (such as VPOP3) which have a permanent connection to the Internet. You may also want to use it on servers which are only connected occasionally via a dial-up connection.

Spamfilter Whitelist & Blacklist

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spamfilter Whitelist & Blacklist The VPOP3 spamfilter has a whitelist and a blacklist for sender addresses. It also has a whitelist and blacklist for words/phrases. You can view these lists in the VPOP3 settings by going to Settings -> Spamfilter ->

550 5.7.1 Relaying not allowed! Bad sender IP address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

550 5.7.1 Relaying not allowed! Bad sender IP address This SMTP error message means that the computer which is sending the message is not permitted to send outgoing messages based on the VPOP3 SMTP Service's Access Restrictions. This is probably because someone is trying to send messages from outside your local network, and you have not configured VPOP3 to allow this. You have to be careful when allowing this, because you may configure VPOP3 to be an open-relay, which is a

Copy Outgoing mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Copy Outgoing mail Sometimes people need to copy outgoing mail for various reasons. There are several ways of doing this in VPOP3 depending on your exact requirements: * Message Monitoring - this copies all outgoing, incoming and/or internal mail sent by/to specific users to another specific user

Data stream contained NUL character

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Data stream contained NUL character Description of the problem NUL characters (bytes with value 0) are not allowed in email messages and should not be transmitted over POP3, SMTP or IMAP4 except in certain circumstances. If an attachment contains such a byte it must be encoded using

How to Forward Messages to an External Address

Anonymous (anonymous@undisclosed.example.com) — 2025-08-18T15:13:06+00:00

How to Forward Messages to an External Address There are two possible methods to forward messages to an external address: * Use this method if it is for a person who might want to receive their email whilst in the office and/or get the mail sent to an external address.

Initial Configuration Tasks

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Initial Configuration Tasks After installing VPOP3, you will need to get into the VPOP3 settings. The easiest way of doing this is to find the VPOP3 Status Monitor in the Windows task tray. Right-click this icon, and choose 'VPOP3 Settings'. (If that doesn't work, see this article to troubleshoot Status Monitor problems). Alternatively, on the VPOP3 PC, you can go to Start

How to limit size of sent mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to limit size of sent mail There are several ways to limit the size of mail which can be sent * Limit the size of mail accepted by the SMTP component of VPOP3 * Limit the size sent for a particular user * Limit size based on 'rules' * Limit size based on

How to configure Mozilla Thunderbird

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to configure Mozilla Thunderbird This article won't show you all the possible settings in Thunderbird, because there are so many. Thunderbird is one of the most powerful & flexible email clients available at the time of writing, especially if you use IMAP4 (with VPOP3 Enterprise).

MX Send Warning - .....

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

MX Send Warning - ..... If you see the text 'MX Send Warning - ' in the VPOP3 status monitor, that means that VPOP3 is trying to send a message to another mail server using the MX send method (direct to the recipient's mail server) and

Out of Disk Space When Sending Mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Out of Disk Space When Sending Mail The first thing you should do is check that there is enough free disk space on the disk where VPOP3 is installed. VPOP3 requires a certain amount of free space before it will allow new messages to be sent, so the disk might not be totally full, but VPOP3 will still report that there is insufficient disk space when you try to send a new message. This buffer zone is designed to help prevent the disk totally filling up, which can cause lots of bigger problems!

Use Download Rules for incoming POP3 message filtering

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Use Download Rules for incoming POP3 message filtering If you have VPOP3 retrieving messages from a POP3 account on an ISP, then you can use Download Rules to do basic filtering on incoming messages. (If you have incoming SMTP, then use SMTP Rules instead) Download rules cannot perform all mail filtering tasks. For more features,

Using VPOP3 Advanced Features with LAN Forwarding

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Using VPOP3 Advanced Features with LAN Forwarding If you are wanting to use any of VPOP3's advanced features (such as mailing lists, message monitoring, wildcard aliases etc) because you are LAN forwarding to a less capable server, then you will usually need to have VPOP3 do all its normal message routing functions initially, then, as the final stage have it forward the messages on to the other server.

421 4.3.2 VPOP3 Too many connections from your IP address - try later

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

421 4.3.2 VPOP3 Too many connections from your IP address - try later If you see this error message when you are sending messages, then it means that VPOP3 has detected too many simultaneous connections from your IP address. This would usually happen if the sender is another mail server as they can make many simultaneous connections when there are lots of messages to send. The error code that VPOP3 gives means that the sender should try sending the messages later, so it should be possible to e…

Socket Error 10061 - The attempt to connect was forcefully rejected

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 10061 - The attempt to connect was forcefully rejected Error 10061 means that the computer which VPOP3 was trying to connect to (probably at your ISP) refused the connection from the computer running VPOP3. There are several possibilities that can cause error 10061:

Socket Error 10503 - No More Data

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 10503 - No More Data Error 10503 means that the connection between VPOP3 and a remote computer (normally your ISP) was dropped at an unexpected time. This is different from the error 10054 in that this is a controlled line drop. One way this can happen is if the ISP's POP3 server uses an obsolete standard which allows it to drop the connection if a POP3 'LIST' command is performed on an empty mailbox. The current standard requires that the connection is not dropped until the clien…

How to automatically forward spam to the PSCS spamtrap

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to automatically forward spam to the PSCS spamtrap Spam filter companies use “spamtraps” to catch samples of spam for analysis so filters can be updated. We do this here as well. Most types of spam are already caught by our spam traps, however sometimes people get lots of spam which gets through the filter because their particular type of spam does not currently get sent to our spam traps.

Custom filtering incoming mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Custom filtering incoming mail If you want to filter incoming mail using custom rules there are a few ways of doing this, depending on your exact requirements. * Download rules - if your incoming mail is via POP3 collection, you want to filter on headers, size etc (not contents)

Download Rules

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Download Rules Download rules are applied to messages downloaded using a POP3 mail collector. To configure the rules, go to the VPOP3 settings, then Mail Connectors -> Mail Collectors -> POP3 General. There is an Edit Download Rules button which brings up the download rule editor. To tell this mail collector to use the download rules, ensure that the

Error Message Handling

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Error Message Handling VPOP3 will normally send an error message to the Main Administrator every time it encounters an error. We recommend you leave it like this in most cases - if an error message occurs repeatedly, then it usually means there's an underlying problem which needs resolving rather than ignoring.

French Webmail Language File

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

French Webmail Language File Copy/paste the text below to a file 'french.lng' or 'francais.lng' in the VPOP3 directory. (French users, feel free to update/correct the text below) #login page logintitle=VPOP3 Login webadminlogin=web admin login webmaillogin=web mail login enterusername=You must specify your VPOP3 username here bookmarksnotsupported=I'm sorry, but your web browser does not support this function. You will have to add this page to your bookmarks manually. loginfailed=Login Faile…

VPOP3 - POP3 Client Connection Problem

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 - POP3 Client Connection Problem These errors occur during the period when VPOP3 is trying to establish a connection to your ISP's POP3 mail server to receive incoming mail. They can mean that you have entered the POP3 Server address incorrectly, or that there is a problem with the network, or that your ISP's mail server is not working properly.

Restricting the number of messages sent

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Restricting the number of messages sent Some ISPs set restrictions on the number of messages that you are allowed to send in a certain time period, eg 50 messages per hour, or the number of messages that you are allowed to send per connection. Restriction of messages per connection

VPOP3 - SMTP Client Connection Problem

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 - SMTP Client Connection Problem These errors occur during the period when VPOP3 is trying to establish a connection to your ISP's SMTP mail server to send outgoing mail. They can mean that you have entered the SMTP Server address incorrectly, or that there is a problem with the network, or that your ISP's mail server is not working properly.

How To Setup VPOP3 Service Security

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How To Setup VPOP3 Service Security VPOP3 can be configured to restrict access to its various services depending on the client computer's IP address. This is useful if you want to allow access from only certain IP addresses (eg within your LAN) and prevent access from other IP addresses (eg the Internet).

550 5.7.1 Unable to Relay for...

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

550 5.7.1 Unable to Relay for... When trying to send emails from your email client software you get an error in your email client 550 5.7.1 Unable to relay for ... This error is happening because you have installed the Microsoft IIS SMTP Service, and your email client is talking to that service rather than to VPOP3.

Socket Error 11001 - Host not found (authoritative answer)

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 11001 - Host not found (authoritative answer) This means that the ISP POP3 or SMTP server which you have told VPOP3 to connect to does not currently exist. This might be that you have mistyped the server address, or that your ISP is having temporary problems, or that you are using an internal

Allow Remote Access to VPOP3 Mailboxes

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Allow Remote Access to VPOP3 Mailboxes Sometimes people want to be able to access their office VPOP3 mail server from a remote site or mobile phone etc. These instructions assume you have a permanent Internet connection (eg ADSL, Cable etc). If you don't have a permanent Internet connection, see

Creating Extra SMTP Services

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Creating Extra SMTP Services In VPOP3 Enterprise (not VPOP3 Basic) you can create multiple SMTP services. This can be useful if you want VPOP3 to listen on different ports and/or have different settings. There are two ways of doing this. Have a single SMTP service listening on multiple ports or IP addresses

How to delete a Mail Collector or Connection

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to delete a Mail Collector or Connection To delete a Mail Collector or Connection in version 3, click on the little waste-bin icon at the left of the green bar on the Mail Collector or Connection settings page. We have made this more obvious in version 4, by including a bigger

Error Messages

Anonymous (anonymous@undisclosed.example.com) — 2025-10-06T15:21:37+00:00

Error Messages This is the place to look if you are trying to trouble shoot a problem and you have received or have access to a specific error message or error code. If instead your problem is that something you think is set up correctly is not working then the best place to look would be the

German Webmail Language Page

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

German Webmail Language Page Copy/paste the text below to a file 'german.lng' in the VPOP3 directory. (German users, feel free to update/correct the text below) #login page logintitle=VPOP3 Login webadminlogin=web admin login webmaillogin=Webmail Anmeldung enterusername=Sie müssen einen Benutzernamen angeben bookmarksnotsupported=I'm sorry, but your web browser does not support this function. You will have to add this page to your bookmarks manually. loginfailed=Anmeldung fehlgeschlagen …

How to Install VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2021-03-08T10:48:40+00:00

How to Install VPOP3 Simply download VPOP3 from the website, and run the installation program and follow the prompts. Occasionally people may have problems with the PostgreSQL part of the installation. If that happens, please contact us either by email at support@pscs.co.uk or by phone to +44 (0)1484 855800, and we will do our best to help.

The ISP needs SMTP Authentication

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

The ISP needs SMTP Authentication If your ISP needs you to use SMTP authentication when sending mail to them, then you just need to tell VPOP3 to use authentication when sending. Click the Mail Connectors button at the top of the page, then click on the relevant

Outlook / Outlook Express is sending mail repeatedly

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Outlook / Outlook Express is sending mail repeatedly If you are using Outlook or Outlook Express you may occasionally find that mail is being sent repeatedly. There are a couple of possible reasons for this which we know of Sending taking too long

Problems sending mail via BT from your own domain

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Problems sending mail via BT from your own domain BT Internet only allow you to send mail through their mail servers from your BT Internet address or other registered address. Attempts to send from other addresses will give you a 553 SMTP error message.

Sender Domain Must Resolve

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sender Domain Must Resolve If you receive an 'SMTP Client Error' something like: 451 (user@domain.com) Sender Domain Must Resolve this means that the ISP's mail server cannot find the domain.com part of the email address. Often this means that the FROM address of the message is invalid, or that the

Signing outgoing mail with DKIM

Anonymous (anonymous@undisclosed.example.com) — 2020-07-22T10:32:40+00:00

Signing outgoing mail with DKIM DKIM, also known as DomainKeys Identified Mail, is a form of email authentication that digitally signs emails to prove that they were sent from authorized domains and aren't fake emails. Companies like Google and Yahoo use DKIM to sign their emails and it is becoming ever more popular.

Spam filter not working

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spam filter not working If the VPOP3 spam filter appears not to be working at all, the first thing to do is to look at the message headers of an incoming message to see if the spam filter is being run at all. Check to see if a header line beginning with X-VPOP3-Spam

Spanish Webmail Language File

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spanish Webmail Language File Copy/paste the text below to a file 'spanish.lng' or 'espanol.lng' in the VPOP3 directory. (Spanish users, feel free to update/correct the text below) #login page logintitle=VPOP3 Login webadminlogin=web admin login webmaillogin=web mail login enterusername=Especificar aca el usuario de Correo bookmarksnotsupported=Disculpe, pero su navegador no soporta esta funcion. loginfailed=Login Fallido - Favor reintente nuevamente invalidlogin=Detalles del login inválidos…

How to use the VPOP3 Status Monitor

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to use the VPOP3 Status Monitor The VPOP3 Status Monitor is a small program which displays a postbox icon (usually red) in the Windows notification area (usually at the bottom right of the screen - by the clock). This icon can be used for quick access to various VPOP3 facilities. Note that the Status Monitor is

Using a Mobile Phone with VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Using a Mobile Phone with VPOP3 Many people want to use a mobile phone to send/receive their email nowadays. This is usually easy to do with VPOP3. The recommended way is to have the phone connect directly to VPOP3 for sending/receiving email. To do this, you need to do three things:

VPOP3 Is Responding Slowly

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 Is Responding Slowly If VPOP3 is responding slowly to users there are several common causes: * The VPOP3 server disk may be badly fragmented. Defragment the server disk(s). Note that sometimes the Windows defragmenter will say that the disk doesn't need defragmenting even if it does, so it is best to do it anyway. Also, there is a better free defragmenter available called

535 Authentication Failed

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

535 Authentication Failed This is an SMTP error meaning that an attempt to authenticate has failed. If this error is appearing when the email client is trying to log into VPOP3, then you can check the VPOP3 'SECURITY.LOG' file which may contain more information, such as an invalid password, unknown username, etc. (This information is not returned in the SMTP session because it would help an attacker).

Socket Error 10048 - Specified Address Already in Use

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 10048 - Specified Address Already in Use This error only normally occurs during VPOP3 startup. It occurs if some other software running on the same machine as VPOP3 is using one of the ports that VPOP3 is already using. This could be a proxy like WinGate, WinProxy or anti-virus software that acts as a proxy, an LDAP server (e.g. Active Directory) or another mail server program (e.g. Exchange Server). The latter two causes are particularly common on

Android - Stock Client

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Android - Stock Client Warning If you use the stock email client from Android 4.x, then be VERY careful if you are using POP3 download. It appears that the stock client will download all the messages from your mail server every time it checks for mail, so you could use a

How to create an SSL Certificate

Anonymous (anonymous@undisclosed.example.com) — 2026-03-23T10:18:43+00:00

How to create an SSL Certificate VPOP3 Enterprise supports SSL certificates for encrypted sessions. The basic mechanism to create an SSL certificate is that you have to generate a CSR (Certificate Signing Request) then send that to a CA (Certificate Authority) who will sign your certificate and give you the certificate back.

Daily Summary is not reporting all Sent messages

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Daily Summary is not reporting all Sent messages For VPOP3 to log outbound messages it needs to be able to work out that the message is FROM: a user whose mail is handled by the local VPOP3. To do this it has to examine the FROM: address in the message header.

How To Encrypt Sessions

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How To Encrypt Sessions VPOP3 Enterprise 2.6 and later supports SSL/STARTTLS encrypted sessions to VPOP3 itself. So, the email client or web browser will encrypt the data passed to VPOP3 so it cannot be intercepted. This requires an SSL Certificate to be created for VPOP3.

-ERR Unknown User

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

-ERR Unknown User -ERR Unknown User is a POP3 error. There are two places you can receive it: * If you receive it as part of a 'POP3 Client Error' email message from VPOP3, then it means that VPOP3 was unable to log on to your ISP's mail server because the ISP POP3 server reported an error

Error message after sending RCPTTO: - error 0 - text 550 5.7.1 Relaying not allowed! Bad sender IP address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Error message after sending RCPTTO: - error 0 - text 550 5.7.1 Relaying not allowed! Bad sender IP address If you get this error message from within Webmail, then it usually means that the SMTP service access restrictions are blocking Webmail from sending mail.

"How To" Articles

Anonymous (anonymous@undisclosed.example.com) — 2026-03-18T20:20:50+00:00

"How To" Articles Installation/Upgrades * Download VPOP3 * Install VPOP3 * Move VPOP3 * Upgrade VPOP3 * Upgrade VPOP3 to version 5.x or 6.x from version 4 or earlier * Upgrade VPOP3 to version 7.x from version 6 or earlier * Upgrade VPOP3 to version 8.x from version 7 or earlier * Upgrade VPOP3 to version 9 or later from version 7 or 8 * Performance Requirements * Installation Checklist General Configuration * Initial Configuration * Users * Add an Alias * Create…

Inbox size is zero but mailbox size is not zero

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Inbox size is zero but mailbox size is not zero In the VPOP3 settings sometimes, on the user account list the “Inbox Count” is shown as zero, but the “Mailbox Size” is not zero. This is not a bug, or mistake - the two figures are showing different things.

SMTP error 'Invalid HELO name'

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

SMTP error 'Invalid HELO name' When sending mail you may get an error from the remote SMTP server saying something like 'Invalid HELO name' This happens if the host name configured in VPOP3 does not look like a valid Internet host name (e.g. 'mail.domain.com'). Some SMTP servers don't bother checking this value because it has no authentication value at all, but a few do check that it looks correct.

ISP needs you to connect on port 587

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

ISP needs you to connect on port 587 Some ISPs will need you to send mail using port 587, instead of port 25. Port 587 is the 'SMTP Submission' port which is commonly used instead of, or as well as, the standard SMTP port 25 for when users are sending mail to a smart host/relay server.

Make VPOP3 retry outgoing messages immediately

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Make VPOP3 retry outgoing messages immediately If VPOP3 has a temporary problem sending a message it will retry it later. When it will retry it depends on how many times it has already tried to send it, and is based on the 'Sender Retry' setting in the Mail Connectors

Outbound Messages Not Appearing in Monitor Target Mailbox

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Outbound Messages Not Appearing in Monitor Target Mailbox For VPOP3 to monitor outbound messages it needs to be able to work out that the message is FROM: a user whose mail should be monitored. To do this it has to examine the FROM: address in the message header.

How to configure Outlook 2003

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to configure Outlook 2003 Email (to be completed) Address Book To configure Outlook to use the VPOP3 global address book, go to Tools -> E-Mail Accounts in Outlook Then choose Add a new directory or address book and press Next Choose Internet Directory Service (LDAP)

How to configure Outlook 2007

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to configure Outlook 2007 Email SMTP Authentication To set up SMTP authentication in Outlook 2007, if your VPOP3 requires it, go to Tools -> Account Settings, select your email account and press Change.... Then, press the More Settings... button

How to configure Outlook 2010

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to configure Outlook 2010 In many ways, configuring Outlook 2010 is a similar to configuring Outlook 2007. The biggest difference you are likely to notice is the new “Ribbon” interface, in place of the traditional menu bar (File, Edit, View, etc.) Email

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

The ping command is a useful way of diagnosing network problems. It's similar to the sonar ping in a submarine. It sends out a signal to a specified machine and waits for a response to be echoed back. * Open a command prompt * Type ping www.pscs.co.uk. You should see a display like this:

Problems accessing VPOP3 Settings

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Problems accessing VPOP3 Settings If you have problems accessing the VPOP3 settings: * Go to Start -> Programs -> VPOP3 -> Configure VPOP3 on the VPOP3 computer. That should open up a web browser and take you to the login page * If VPOP3 doesn't show the login page, and shows a '403' error page instead, that means that the access restrictions for the WebMail service have been restricted so that this computer cannot access the WebMail service.

Problems sending messages to spam@

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Problems sending messages to spam@ If a VPOP3 user forwards a message to spam@, then the VPOP3 spam filter will train itself that that message was spam. If, when you forward the message, you get an error message like: Subject: Mail Delivery Failure Delivery Failure Report. The following message was incorrectly addressed. Recipient: "spam" is unrecognised.

How To Upgrade VPOP3

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How To Upgrade VPOP3 Note: if you are upgrading to VPOP3 version 5 or later from version 4 or earlier, please see How To Upgrade VPOP3 to version 5 Upgrading VPOP3 is a straightforward process. Download VPOP3 from our web site and ideally back up your current installation just in case something goes wrong. Then simply run the installer that you downloaded and install it over the top of your existing VPOP3. All your settings and mail will be preserved.

Move VPOP3 Version 3 or 4 to a new PC

Anonymous (anonymous@undisclosed.example.com) — 2019-11-12T16:09:08+00:00

Move VPOP3 Version 3 or 4 to a new PC Moving VPOP3 Version 3 or 4 to a new PC is slightly different from moving earlier versions, because of the database system. The summary of steps is: * Stop VPOP3 on the original PC * Manually make a backup of the database on the original PC

VPOP3 2.x crashes when user tries to download mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 2.x crashes when user tries to download mail If VPOP3 2.x crashes when a user tries to download mail, there are a few possible causes we know of: * A virus scanner or Internet security software is interfering with the connection between VPOP3 and the email client and is either terminating VPOP3 deliberately, or is blocking VPOP3 causing another part of it to crash

Socket Error 10060 - Operation Timed Out

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 10060 - Operation Timed Out This error is quite self explanatory. It means that Windows reported that a connection attempt or idle connection timed out. If this error occurs during a connection attempt (eg in a VPOP3 - SMTP Client connection problem error message), then it means that Windows couldn't connect to the ISP mail server within a fixed time (the timeout limit is fixed within Windows itself). This problem can either mean that your ISP is having a problem, that you are con…

Socket Error 11002 - Host not found (Non-Authoritative answer)

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Socket Error 11002 - Host not found (Non-Authoritative answer) This means that VPOP3 is not getting a response from a DNS server when it is trying to look up the name of the ISP's mail server(s). Usually this means that Windows either does not know the address of a valid

Anonymous (anonymous@undisclosed.example.com) — 2026-03-26T13:20:22+00:00

Configuring Calendar on iOS

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Configuring Calendar on iOS These instructions are for configuring a new Calendar account on iOS for iPhone, iPad and iPod Touch. The version of iOS used for these instructions is iOS v6.0, but they will probably work or help with other versions of iOS.

Configure SRS

Anonymous (anonymous@undisclosed.example.com) — 2025-08-18T15:28:11+00:00

Configure SRS In VPOP3 8.8 and later, you can use Lua scripting to implement 'SRS' (Sender Rewriting Scheme') in VPOP3 This involves adding a couple of functions to rewrite outgoing return paths in 'relayout.lua' or 'mxout.lua' as appropriate and a couple of functions to redirect rewritten bounce message recipients in 'smtpsvr.lua'

-ERR Password supplied for "xx" is incorrect

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

-ERR Password supplied for "xx" is incorrect If you receive a 'POP3 Client Error' something like: -ERR Password supplied for “xx” is incorrect this means that the password on the 'In Mail' tab in VPOP3 for the indicated user is entered incorrectly.

Error 0x80040201 when sending mail in Outlook

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Error 0x80040201 when sending mail in Outlook Often this is because there is 'Read Receipt' stuck in the Outlook out queue, but these do not show in the Outlook Outbox view. We found this article helpful: If you need help with following this, you can call us, but it

Configuring iCal on Mac OSX to connect to VPOP3's CalDAV service

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Configuring iCal on Mac OSX to connect to VPOP3's CalDAV service This requires VPOP3 v6 or later. The following instructions are for Mac OS X v10.7.5 but should work with similar versions. We have not been able to create an account by going to System Preferences

Using IMAP4 with VPOP3 Enterprise

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Using IMAP4 with VPOP3 Enterprise VPOP3 Enterprise supports IMAP4 email clients (VPOP3 Basic does not). With IMAP4 the email folders and messages are stored on the mail server. The email client then synchronises with the server. Also, unlike with POP3, several things can access the same mailbox at once.

Installation checklist

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Installation checklist This list contains some things you may want to check before or after installing VPOP3 to make sure it's not going to encounter any common issues. Before installation * Make sure that VPOP3 is not installed on a RAID 5 or RAID 6 array.

Is it possible to stop messages that VPOP3 downloads from being marked as read?

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Is it possible to stop messages that VPOP3 downloads from being marked as read? VPOP3 does not mark messages as read when it downloads them. In fact, the POP3 protocol doesn't have a system available for marking messages as read, so it is impossible for VPOP3 to mark messages as read.

ISP needs SSL connection

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

ISP needs SSL connection A few ISPs use a non-standard and not recommended system of encrypting connections to their SMTP mail servers. These generally are called 'SSL' connections and work on an alternate port other than the standard SMTP port 25. (The correct way to encrypt connections is to use a system called TLS which works on the standard SMTP port).

LAN Forward Warning: 452 (4.3.1 Insufficient system resources)

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

LAN Forward Warning: 452 (4.3.1 Insufficient system resources) If you get this message in VPOP3 it means that VPOP3 is trying to forward a message on to another mail server (probably Microsoft Exchange Server), and that other server is rejecting the message with the error

Messages being put into an 'Unwanted' folder

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Messages being put into an 'Unwanted' folder If incoming messages are being put into a folder called 'Unwanted' this may be due to the default Samsung Galaxy mail client's spam filtering. See:

Performance Requirements

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Performance Requirements The performance requirements for VPOP3 depends on many factors, so we can't give specific details for any scenario. How to detect limiting factors * Use the Windows Performance Monitor (perfmon.msc) * Add counters for:

Restore selected mail folders or mailbox in VPOP3 v5 or later

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Restore selected mail folders or mailbox in VPOP3 v5 or later (This option is only available in VPOP3 Enterprise) First - if the problem is that messages were deleted very recently (the default is within 3 days), you can probably use the Undelete feature in VPOP3.

Anonymous (anonymous@undisclosed.example.com) — 2026-03-26T13:21:22+00:00

Anonymous (anonymous@undisclosed.example.com) — 2026-03-26T13:23:19+00:00

Anonymous (anonymous@undisclosed.example.com) — 2026-03-26T13:15:40+00:00

SMTP Rules

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

SMTP Rules Download rules are applied to messages which arrive at VPOP3 using SMTP - either locally sent messages, or incoming messages received through an SMTP mail feed. To configure the rules, go to the VPOP3 settings, then Services -> SMTP Service

Troubleshooting Tips

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Troubleshooting Tips Telnet One of the most basic, and useful, tools for troubleshooting email systems is a Telnet client. Installing Telnet Client Unfortunately, since Windows XP, Microsoft do not install the Telnet client into Windows by default, so you may need to install the Telnet client yourself.

How To Upgrade VPOP3 to version 5 or later

Anonymous (anonymous@undisclosed.example.com) — 2019-11-08T15:37:52+00:00

How To Upgrade VPOP3 to version 5 or later Upgrading VPOP3 is usually a straightforward process. Download VPOP3 from our web site and back up your current installation just in case something goes wrong. Then simply run the installer that you downloaded and install it over the top of your existing VPOP3. All your settings and mail will be preserved.

How To Move VPOP3 Version 2 to a New Folder/Drive on the same PC

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How To Move VPOP3 Version 2 to a New Folder/Drive on the same PC (Also applies to version 1.x) To move VPOP3 to a new folder or drive on the same PC you should go through the following steps: * Copy the VPOP3 directory and subdirectories from the old folder to the new folder.

How To Move VPOP3 Version 2 to a New PC

Anonymous (anonymous@undisclosed.example.com) — 2019-11-12T16:06:44+00:00

How To Move VPOP3 Version 2 to a New PC (Also applies to version 1.x) To move VPOP3 to a new PC you should go through the following steps: * Copy the VPOP3 files * Copy the VPOP3 directory and subdirectories from the old PC to the new PC. (If you are moving to Windows Vista/2008/7/2012/8 or later, do NOT copy the files to a 'Program Files' folder on the new PC. Recent versions of Windows have special protection for those folders, which is not compatible with VPOP3)

Error message: VPOP3 Alert - Non-existent user -

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Error message: VPOP3 Alert - Non-existent user - If you receive an error message like: Subject: VPOP3 Alert - Non-existent user - Delivery Failure Report. There was incoming mail for non-existent user "". This means that VPOP3 downloaded a message using POP3 and it was addressed to an email address which does not exist.

VPOP3 Deleting messages as 'old' messages

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 Deleting messages as 'old' messages If VPOP3 says 'deleting old message' in the status window activity log that means that it has seen the unique ID of that message before, longer ago than the time specified for VPOP3 to leave messages on the server, so it thinks that the message is an old message, and so deletes it.

VPOP3 re-downloading old messages from the ISP POP3 server

Anonymous (anonymous@undisclosed.example.com) — 2026-01-05T09:31:47+00:00

VPOP3 re-downloading old messages from the ISP POP3 server If you tell VPOP3's POP3 mail collector to leave messages on the ISP's server for a few days, you may find that sometimes VPOP3 will redownload all the messages from the ISP mailbox again.

VPOP3 Server Access Not Allowed

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

VPOP3 Server Access Not Allowed If you get an error like: -ERR VPOP3 Server access not allowed! when trying to access VPOP3, then this means that the relevant server's IP Access Restrictions defined in VPOP3 do not allow access from your client computer.

When sending mail, VPOP3 adds 'PRVS=...' to the sender address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

When sending mail, VPOP3 adds 'PRVS=...' to the sender address This is because VPOP3 version 5 and later support BATV. BATV helps to eliminate 'backscatter spam', where someone else sends spam pretending to be from you, and then you receive all the bounce messages from those messages. BATV encodes the sender address in a special way so that VPOP3 can detect that a bounce message is in response to a message that you actually sent.