From the web client, all is well.
From Thunderbird or Outlook Express, receiving mail via pop3 or IMAP is fine. Also sending to local addresses (domains defined in Zimbra) is fine. Outbound email to outside addresses, like hotmail, etc. fail with 'relay denied'.
Because the outbound mail works fine out of the web client, I know the receiving party is accepting mail - no reverse look up problems at their end, etc.
I've tried many combinations of Zimbra settings with no luck. I've read everything I can find in the forums, but can't get it to work.
Anyone have a similar problem they've been able to solve?