i run a ZCS for 1 year without any problems. But today i tried to send a email from another server with postfix. Every Email-provider is able to receive this email (gmail, gmx, freenet, ...) but not my zimbra-server ;-(

The logs of postfix show that the connection ist timed out:

Mar 22 18:11:02 mee2 postfix/smtp[14755]: 1ABD0CAA87B: to=<stefan@mydomain.org>, relay=none, delay=3323, delays=3302/0
.02/21/0, dsn=4.4.1, status=deferred (connect to mail.mydomain.org[]:25: Connection timed out)
Do I have to change the ZCS-Config? What happens?

Thank you and best regards