I am really a newbie on this zimbra.
This is my problem.

I have an internal domain abc.com in my zimbra. This is fully working, user@abc.com can send/receive no problem.
Then I closed this domain then created a new mail server in exchange called mail.abc.com. I changed the MX record to point to that new mail.abc.com. From external mail, yahoo, gmail, I can send to user@abc.com but from zimbra account, when I try to send to user@abc.com it will bounce. looks like it still tries to send to internal domain abc.com.

thanks in advance....