Hello i'm having the same problem,
From last night till now i have made only 1 modif in the server but now the dovecot server is not working anymore... i've followed to the letter the tutorial of perfect server 12.10 everything worked out just fine and now i get only for sending emails
Jan 29 15:57:07 www postfix/error: 2F24E5D1FA: to=<firstname.lastname@example.org>, relay=none, delay=713, delays=653/60/0/0.02, dsn=4.3.0, status=deferred (mail transport unavailable)
What could be the problem pls help !!!