https://wiki.pscs.co.uk/ 2026-06-22T20:56:20+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: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:alternative_method_of_automatically_starting_vpop3?rev=1542192349&do=diff Alternative method of automatically starting VPOP3 VPOP3 usually automatically starts as a Windows service. Sometimes this does not work, either because other services need to start first, or Windows is going very slowly at startup, causing the database service to time out, or there are certain database control files which did not get cleared after a previous Windows shutdown. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:automatically_forwarding_spam_to_the_pscs_spamtraps?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:c_error_popup?rev=1542192349&do=diff C++ Error Popup If VPOP3 crashes with a C++ error popup window, that means that an 'exception' has been thrown - something unusual has happened, and VPOP3 doesn't know how to recover automatically. Often these are due to database errors. There are two places you can look for the cause of the error: text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:encrypt_sessions?rev=1542192349&do=diff 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. text/html 2026-06-05T07:26:39+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:repairing_corrupted_database?rev=1780644399&do=diff Repairing corrupted database With PostgreSQL (as with most high-end databases) the database system will automatically recover after power failures etc, if it can. If it can't then there is no manual 'repair' function, because the data cannot totally be recovered (or it would automatically have been recovered). 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: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 2020-09-03T15:07:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:upgrade_vpop3_to_version_8?rev=1599145654&do=diff Upgrading VPOP3 to version 8.x from v7 or earlier VPOP3 v8.x uses PostgreSQL 10 as its database engine, which is the latest supported 32 bit version of PostgreSQL. Later versions of PostgreSQL are 64-bit only, which means we cannot use them while continuing to support 32 bit versions of Windows. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_status_monitor_problems?rev=1542192349&do=diff VPOP3 Status Monitor Problems The VPOP3 Status Monitor is the program which shows the little (usually red) postbox icon in the Windows task tray. This usually launches automatically from the Windows startup group. This program is VPOP3Status.EXE on the disk, or can be run manually from 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:autoupdate_process_failed_with_error_code_786432?rev=1542192349&do=diff Autoupdate process failed with error code 786432 This is actually a success result from the automatic update program, which is incorrectly being identified as an error in VPOP3. This will be fixed in VPOP3 v6.15 In fact, this means that the automatic update program needed to be restarted automatically because it had updated itself. It is not a problem. Future versions of VPOP3 will suppress this error message. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:backup_vpop3?rev=1542192349&do=diff How to Backup VPOP3 By default VPOP3 v3 and later will automatically perform a daily backup of the database into a file called DBBACK-x.DMP, where the backup file rotates on a weekly basis (DBBACK-0.DMP is Sunday's backup, DBBACK-1.DMP is Monday's backup, etc). 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:database_disk_caching?rev=1542192349&do=diff Database & Disk Caching Disk Caching One key point is that, like all other high-end databases, PostgreSQL should not be run on a server with disk level write back caching. With write back caching, the disk will report data as being written to disk when it is still in the disk's cache memory. If the power then fails, this data is lost and can cause database corruption. As long as the database server really knows when the data has been written to disk, power failure will not cause database corru… text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:delete_an_outgoing_message?rev=1542192349&do=diff Delete an outgoing message To delete an outgoing message, go into the VPOP3 settings, then go to the 'Users' page. At the top of the page will be a line saying Outgoing Message Queue. Click on that line, and this will show you all the messages waiting to go out. You can now select the message(s) in question, and press the text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:exceptions?rev=1542192349&do=diff Exceptions An exception happens if VPOP3 encounters a problem it did not expect. In some cases it can recover automatically, but in other cases that isn't possible. Common causes VPOP3 2.6 and earlier In VPOP3 2.6 and earlier it was quite common for there to be database corruption problems with the SQLite database which was used in those versions. 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:ghost_folders?rev=1542192349&do=diff IMAP4 'Ghost Folders' Sometimes your IMAP4 email client may show folders in the folder tree, but when you select them, you get an error that the folder does not exist. This happens because IMAP4 has the concept of being able to 'subscribe' to folders - this means that you can hide folders by unsubscribing from them. text/html 2026-03-18T20:20:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:how_to?rev=1773865250&do=diff "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… text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:install_the_status_monitor_on_other_pcs?rev=1542192349&do=diff How to install the VPOP3 Status Monitor on other PCs The VPOP3 status monitor icon is run by a separate program from VPOP3, which communicates with VPOP3 using TCP/IP. This means that this program can be installed on any PC which can connect to the VPOP3 computer using TCP/IP (on port 5109 by default). text/html 2021-03-08T10:48:40+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:install_vpop3?rev=1615200520&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:installation_conflicts?rev=1542192349&do=diff Installation conficts During installation, the installer program does some basic checks for conflicting software. This is software which is providing the same services as the VPOP3 software - i.e. SMTP, POP3 and/or LDAP services. For POP3/SMTP it will show the text which the conflicting software announces itself as. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:installed_new_router_and_now_nothing_works?rev=1542192349&do=diff We installed a new router and now nothing works If you installed a new router on your network and left it at the default settings, you may find that VPOP3 doesn't seem to work afterwards. This is because it may be that the new router allocates new IP addresses on your network. 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 2026-04-06T17:57:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:make_vpop3_redownload_messages_from_isp?rev=1775498220&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:mozilla_thunderbird?rev=1542192349&do=diff 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). text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:mx_send_warning?rev=1542192349&do=diff MX Send Warning - ..... If you see the text 'MX Send Warning - <error message>' 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 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: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 2020-06-29T10:43:58+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:upgrade_vpop3_to_version_7?rev=1593427438&do=diff How to upgrade VPOP3 to version 7 or later from version 6 or earlier As usual the process to upgrade is simply to install the later version over your existing installation (do not uninstall anything first). The below is technical information detailing an extra step performed by the installer in this particular upgrade step. text/html 2026-03-18T20:49:54+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:upgrade_vpop3_to_version_9?rev=1773866994&do=diff Upgrading VPOP3 to version 9.x from v7 or v8 VPOP3 v9 and later requires a 64 bit version of Windows 8.1 or later VPOP3 v9.x uses PostgreSQL 18 as its database engine. This can only easily be upgraded from PostgreSQL 9.3 or later, which means it must be an upgrade of VPOP3 v7 or later. If you are using an earlier version of VPOP3, then upgrade it to v8.7 first, then upgrade to v9 or later text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_access_security?rev=1542192349&do=diff 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). text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_is_using_a_lot_of_disk_space?rev=1542192349&do=diff VPOP3 is using a lot of disk space If VPOP3 is using a lot of disk space, the problem is usually that there is lots of data there, so it has to use the disk space. Message Storage In VPOP3 version 5 and later, all users' messages are stored in the database, so they will occupy space in the VPOP3\pgsql\data folder. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:vpop3_xxxxx_server_access_not_allowed?rev=1542192349&do=diff 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. text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:whitelist_blacklist?rev=1542192349&do=diff 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 -> text/html 2018-11-14T10:45:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.pscs.co.uk/how_to:your_connection_has_been_blocked_temporarily_-_try_again_later?rev=1542192349&do=diff Error message: Your connection has been blocked temporarily - Try again later If you get an error message in your email client software saying Your connection has been blocked temporarily - Try again later or Server access temporarily blocked! Please try again later