Oftentimes, you may need to just delete all messages in queue (for example, when your script has gone mad and generated too many messages to handle, once you’ve stopped postfix). It’s quit ...
If you’re getting the "5.3.4 Messag exceeds fixed limit” error, check on the default vs set values in your /etc/postfix/main.cf using postconf -d (for the default) and postconf -n (for the ...