EDIT: Just saw your addition: "I'll post the result of zmprov gacf, and zmlocalconfig in a while."
and your /etc/hosts lines
mynetworks configuration, that's what's causing your problem. Don't change any of the ports that Zimbra uses unless you know what you're doing and what you're trying to achieve.
Got it. Thanks you all.
-hence why it would have been easier to post your config (zmprov gacf, zmlocalconfig, main.cf, hostsfile etc) earlier...it's like unraveling a thread to get to the source otherwise
Yes, all is okay now. Thanks for your help.