I have mailman setup on another server I'm trying to send mail to it but my Zimbra logs are showing:
Dec 17 11:41:10 zimbraserver postfix/qmgr: 42F15290009C: to=<firstname.lastname@example.org>, relay=none, delay=597, delays=597/0.01/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)
I've been following the wiki.
Mailman is running on the other server, newalias was issued, and I did all the zmprov's in the example.
I'm not sure if this is an issue on the Zimbra server or the host that has mailman.