Postfix Delivery Errors

If your using Gmails SMTP relay and receive either of the following errors, switch your outbound mail to use port 587.

Show Postfix errors;
tail -f /var/log/syslog
Look for either of these;
delivery temporarily suspended: connect to
delivery temporarily suspended: lost connection with

The fix;
vi /etc/postfix/
Update the realyhost;
relayhost =


Postfix send error

Symptom is no email is being received
tail /var/mail/root contains the following error:
Diagnostic-Code: X-Postfix; unknown user:

When you install postfix if your hostname includes your domain then Postfix thinks its receiving mail for the domain, to fix:
vim /etc/postfix/
remove [] from mydestination section

restart postfix and retest
postfix stop
postfix start