Also, please examine your mail log in ISPConfig (Monitor -> Show Mail Log [under Logfiles]). If you find it simpler, you may access the same information by entering the following in a terminal:
Code:
tail -f -n 50 /var/log/mail.log
(press Ctrl+C to stop monitoring the log)
Do repeated errors that seem relevant to your problem appear in the log? You should see errors appended to the log in real-time, provided that you use
tail's -f switch, as in the example above.
I've followed those "Perfect Server" tutorials, too, and one issue I've encountered is that there's no mention of the
mydestination directive within
/etc/postfix/main.cf and the trouble that arises if its misconfigured.
Edit
/etc/postfix/main.cf and modify the line that contains the
mydestination directive such that the machine's hostname is not included, leaving only
mydestination = localhost, localhost.localdomain. Restart Postfix with:
Code:
service postfix restart
In my own experience, if this is not done, virtual mailboxes will have trouble receiving mail.