Knowledge Base
Frequently asked questions and troubleshooting guides for all Servolutions products.
POPcon and POPcon PRO
Exchange Server Configuration Guides
- Configuration of Exchange 2013 or 2016 Server
- Configuration of Exchange 2010 Server
- Configuration of Exchange 2007 Server
- Configuration of Exchange 2003 Server
- Configuration of Exchange 2000 Server
- Configuration of Exchange Server 5.5
Frequently Asked Questions
- How can I transfer my POPcon configuration settings to a new server?
- How to connect to Gmail with modern authentication / OAuth2
- Connect to Microsoft 365 or Outlook online accounts with OAuth2
- "530 5.7.1 Client was not authenticated" error from Exchange
- Exchange does not accept emails larger than 10 MB — how to increase the limit
- "452 4.3.1 Insufficient system resources" error from Exchange
- "550 5.7.1 Unable to relay" error from Exchange
- There are .msg files in the POPcon folder with undistributed emails — how to redistribute them
- Exchange 2013 SMTP error "451 4.7.0 Temporary server error. Please try again later. PRX"
- Emails to unknown Exchange recipients remain stuck in POPcon's queue
- Does POPcon work with Exchange 2010, 2007, 2003, 2000, 5.5, SBS editions?
- Emails from a mailing list are not distributed correctly
- All emails get forwarded to the postmaster because they "do not have local recipients"
- POPcon hangs when my virus scanner deletes infected .msg files
- Can I trigger mail retrieval from the command line?
- Why are emails to unknown recipients in my domain not forwarded to the postmaster?
- POPcon downloads email fine but cannot reach my Exchange server
- BCC recipients do not receive the email — TO: and CC: recipients do
- How to configure POPcon to work with an ISA Server (proxy)
- "554 5.5.2 No valid recipients" error from Exchange
- POPconAdmin does not work or cannot communicate with the POPcon service
- Will I lose emails if Exchange is down when POPcon tries to deliver?
- Is there a log of POPcon's actions — where can I find it?
- How to get rid of emails stuck in POPcon's delivery queue
- All emails are suddenly tagged as SPAM after working fine for a long time
- POPcon does not install on my machine — alternative installation method
- Exchange SMTP connection unexpectedly closed, or "454 5.7.3 Client does not have permission to submit mail"
- How to resend already-downloaded messages
- Configuring POPcon for a branch office that handles only part of a domain
- How to diagnose malfunctioning antispam blacklist server lookups
- "Mail transfer to Exchange failed: Connection to host denied"
- "550 5.7.1 Requested action not taken: message refused" from Exchange
- POPcon delivers email to both the real recipient AND a catch-all mailbox name
- POPcon says it "drops copies" of downloaded email — what does this mean?
- "550 5.5.1 user unknown" or "503 5.5.2 need Rcpt command" from Exchange
- Can POPcon download email from AOL accounts via IMAP?
- Can POPcon download email from Gmail accounts?
- "Out of Office" replies go to internal users but not to external internet senders
- Why does POPcon need to know the "accepted domains" on the POP3/IMAP config tab?
- How to enable non-delivery reports (NDRs) for external senders in Exchange 2003
- Mail does not reach mail-enabled public folders
- Only messages under 10 MB come through — does POPcon impose a size limit?
- Windows Data Execution Prevention (DEP) is crashing the POPcon antivirus engine
- "530 5.7.0 Must issue a STARTTLS command first" or similar STARTTLS error from Exchange
- Spam checking takes 30 seconds per message — why is it so slow?
- "[blacklist] could not be tested and will not be used" — what does this mean?
- Emails to mail-enabled public folders arrive as "posts" instead of emails
- How does the POPcon PRO antispam feature work, and why is it not 100% accurate?
- What is the shortest mail download interval POPcon supports?
- POPcon moved emails to TOOLARGE or BADMAIL folders — how to resend them
- "421 4.4.1 Connection timed out" from Exchange 2007
- Exchange 2007 only accepts one or a few messages at a time from POPcon
- "Exchange aborted receiving the message after N bytes" error
- Why does my distribution group not accept emails from external senders?
- How to forward some accounts to a non-local mailbox on the internet
- "552 5.3.4 Header size exceeds fixed maximum size" from Exchange
- How to have non-delivery reports (NDRs) sent for unknown users
- "421 4.4.2 Message submission rate for this client has exceeded the configured limit"
- How to have NDRs sent for emails that are too large instead of moving them to TOOLARGE
- "Could not reach Exchange SMTP server — check that IP port 25 is not blocked"
- "530 SMTP authentication is required" — what does this mean?
- IONOS blocks non-delivery reports and out-of-office messages
- I installed CSCatchAll and configured a catch-all account but it does not seem to work at all! What can I check?
- How do I configure CSCatchAll? The Administrator utility only allows me to enter a license code.
- How to protect Wordpress sites with BotFence
ChangeSender
- ChangeSender is installed but the sender address is not changing
- How to restrict users' choices for Send-As addresses in ChangeSender
- How to use the same sender address for two Exchange mailboxes
- How to disable the ChangeSender add-in for all users in a terminal server / Citrix environment
MultiSendcon
- "504 5.7.4 Unrecognized authentication type" when using Office 365 SMTP relay
- How to manually create the MultiSendcon Send Connector in Exchange
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