https://wiki.pscs.co.uk/ 2026-05-06T13:12:01+00:00 https://wiki.pscs.co.uk/ https://wiki.pscs.co.uk/_media/wiki:dokuwiki.svg text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:seeing_where_a_message_came_from?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:training_the_spam_filter?rev=1542192349&do=diff Training the VPOP3 Spam Filter The VPOP3 spam filter has a couple of mechanisms which can be used to 'train' it to distinguish between spam and not-spam. Bayesian Filter The Bayesian filter this looks at words in messages sent and received and their probabilities of being contained in spam and not-spam, and works out an overall probability of the message being spam or not-spam based on the combination of those probabilities. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:backscatter?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:err_unknown_user?rev=1542192349&do=diff -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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:error_message_handling?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:pop3_client_problem?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:sender_policy_framework?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:use_the_vpop3_status_monitor?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:attachments_have_been_removed_or_renamed?rev=1542192349&do=diff Attachments have been removed or renamed If you have received an email and one or more of its attachments have been removed or renamed, it might be a result of Attachment Filtering. You can inspect the filtering rules by going to Administration Settings -> Settings -> text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:err_can_t_open_the_message_file_-_it_s_gone?rev=1542192349&do=diff -ERR Can't open the message file - it's gone! If VPOP3 receives the error message “-ERR Can't open the message file - it's gone!” from your ISP's POP3 server when it is downloading messages, this is a symptom of a fundamental bug in your ISP's POP3 server. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:exchange_2007?rev=1542192349&do=diff 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. text/html 2025-08-18T15:13:06+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:forward_messages_to_an_external_address?rev=1755529986&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:initial_user?rev=1542192349&do=diff Initial User When you install VPOP3 it will ask you to create an initial user. This counts towards your user count and is created as your initial administrator account. More administrator accounts can be created later if you wish, and you can remove the initial user if you wish. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:out_of_disk_space_when_sending_mail?rev=1542192349&do=diff 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! text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:smtp_client_problem?rev=1542192349&do=diff 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… text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:spam_filter_not_working?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:transmission_receipt?rev=1542192349&do=diff Transmission Receipt Message This is not an error message, but we are listing it here because it confuses some people. VPOP3 sends a 'Transmission Receipt' when a message is sent out, and it contains a header asking for the receipt. The default configuration is that it will send the transmission receipt if the sender asks for a read receipt. text/html 2026-01-05T09:31:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_re-downloading_old_messages_from_isp_pop3_server?rev=1767605507&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:421_4.3.2_vpop3_smtp_server_access_disabled_-_content_scanner_problem?rev=1542192349&do=diff 421 4.3.2 VPOP3 SMTP Server access disabled - content scanner problem! This usually happens if the “VPOP3 AV” virus scanner has a problem it can't automatically recover from. This may be a fatal error, or a licencing issue. You can check this on the Settings text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:calendar_on_ios?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:copy_outgoing_mail?rev=1542192349&do=diff 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 text/html 2026-03-23T10:18:43+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:create_an_ssl_certificate?rev=1774261123&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:data_stream_contained_nul_character?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:err_password_supplied_for_xx_is_incorrect?rev=1542192349&do=diff -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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:error_expanding_recipient_-_nesting_level_too_deep?rev=1542192349&do=diff Error expanding recipient - Nesting Level too deep You receive an error message saying: Error expanding recipient "<email address>" Nesting Level too deep (51) Check the configuration for loops (Note the '51' number may be slightly different - that's the nesting level - anything over 50 is detected as an error) text/html 2025-10-06T15:21:37+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:error_messages?rev=1759764097&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:exchange_2003?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:french_webmail_language_file?rev=1542192349&do=diff 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… text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:german_webmail_language_file?rev=1542192349&do=diff 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 m&uuml;ssen 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 … text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:iphone?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:no_transport_provider_is_available?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:pop3_client_connection_problem?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:quarantine?rev=1542192349&do=diff Spam Quarantine By default, when the VPOP3 spam filter detects a message as being spam, it will go to the user's quarantine. Users can release messages from the quarantine by going to their webmail page and selecting the message from the quarantine list there. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:rbl_checking_not_working_in_vpop3_enterprise?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:sender_domain_must_resolve?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:set_as_administrator?rev=1542192349&do=diff How to Set a User as Administrator VPOP3 has two 'types' of administrator. * Users who can administer VPOP3, and log in and change settings etc. These are normal users, but have the Administrator box checked on the User -> General settings for that user. These user have a red key icon in the users list. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:smtp_rules?rev=1542192349&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:timeout_problems_when_sending_or_receiving_attachments?rev=1542192349&do=diff Timeout problems downloading/uploading messages with attachments There are various possible reasons for this, usually to do with third party internet security software but they may also be associated with Windows TCP/IP or dial-up adapter issues. You may not have problems with other software, but that doesn't mean the problem is being caused by VPOP3. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:too_many_logins?rev=1542192349&do=diff "Too many logins" error message VPOP3 version 4 and later have a limit on the number of concurrent logins which can be received for a single user or from a single IP address. This is to prevent a single user from bringing the server down. The current default limits are 20 per user, or 1000 per IP address (to allow multiple people sharing a NAT IP address) text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:troubleshooting_tips?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:using_a_mobile_phone_with_vpop3?rev=1542192349&do=diff 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: text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:using_vpop3_with_microsoft_exchange?rev=1542192349&do=diff 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. text/html 2018-12-05T15:25:41+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:v3_-_move_to_a_new_folder?rev=1544023541&do=diff How to move VPOP3 V3 to a new folder This guide assumes you want to move the whole of VPOP3 (including the message store) to a new folder on the same PC * Stop VPOP3 * Stop PostgreSQL * Remove the PostgreSQL service * Move VPOP3 to the new folder text/html 2019-11-12T16:09:08+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:v3_-_move_to_a_new_pc?rev=1573574948&do=diff 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 text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_alert_-_non-existent_user?rev=1542192349&do=diff Error message: VPOP3 Alert - Non-existent user - <username> If you receive an error message like: Subject: VPOP3 Alert - Non-existent user - <username> Delivery Failure Report. There was incoming mail for non-existent user "<username>". This means that VPOP3 downloaded a message using POP3 and it was addressed to an email address which does not exist. text/html 2025-10-06T15:24:19+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_antivirus_update_error_-_error_11?rev=1759764259&do=diff VPOP3 Antivirus Update Error - Error 11 If you receive an “Error 11” when VPOP3 Antivirus is attempting to upgrade, then this means that it cannot download the antivirus updates from the Internet * Make sure you are using the latest version of the VPOP3AV plugin. You can check the version in the Settings text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_antivirus_update_error_-_error_55?rev=1542192349&do=diff VPOP3 Antivirus Update Error - Error 55 If you receive an “Error 55” when VPOP3 Antivirus is attempting to upgrade, then this means that the virus definition database is not readable. If you have VPOP3 Antivirus version 1.0.6 or earlier (check on Settings text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_historical_logger_backlog?rev=1542192349&do=diff VPOP3 Historical Logger Backlog This problem is primarily related to VPOP3 versions 2.5 -> 2.6. Theoretically it could happen on later versions, but would be extremely unusual (see the note at the bottom if you are using version 3.0 or later) You get an error message with subject text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_not_starting_properly?rev=1542192349&do=diff VPOP3 Not Starting Properly If VPOP3 is not starting properly, then the first thing to check is whether the database server is starting. In VPOP3 v3 and later, VPOP3 uses a PostgreSQL Database server for data storage, so if the database server is not running, VPOP3 will not be able to start properly. In this case, the VPOP3.EXE process may appear in Task Manager, but it won't respond to anything, or it may appear in Task Manager and then stop after a short period. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:when_sending_mail_vpop3_adds_prvs_.._to_the_sender_address?rev=1542192349&do=diff 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.