itemprop="text"> I'm running exim4 (4.76) on Ubuntu 12.0.4.4. exim4 is set up to handle mail for mydomain.com. I have aliases set up that forward a@mydomain.com to b@gmail.com. I have SpamAssassin set up to work in conjunction with exim4 (via sa-exim.conf). Sometimes spam is sent to a@mydomain.com and SpamAssassin assigns it a low enough score that it forwards it to b@gmail.com. GMail rejects the message as spam, so my exim4 server attempts to send a message back to the spam address saying: This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: b@gmail.com (generated from a@mydomain.com) SMTP error from remote mail server after end of data: host gmail...