======Problems sending messages to spam@<your domain>======
If a VPOP3 user forwards a message to spam@<your domain>, then the VPOP3 spam filter will [[training_the_spam_filter|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.
  
that means that VPOP3 saw the message as an incoming message. VPOP3 does not treat the 'spam@' or 'notspam@' email addresses as a valid email address for incoming messages, only for ones sent by VPOP3 users. This is to prevent other people from 'polluting' the spam filter training by sending messages to spam@yourdomain or notspam@yourdomain.

To be able to send messages to spam@ or notspam@ the sender has to send mail directly to the VPOP3 server using SMTP, either using [[require_smtp_authentication|SMTP authentication]], or from an IP address which is specified as "allow unauthenticated access" in the SMTP service IP access restrictions.