I'm running Zimbra Desktop Beta 2 on a Mac OS X Leopard system, and can't seem to get it connected to my IMAP4 account over SSL.

If I configure it without SSL it works fine. But if I enable SSL (and set the port to 993), I get the following error:

"AUTHENTICATE PLAIN failed"

I've turned on IMAP logging, and it's clear that Zimbra is successfully connecting to the IMAP server before receiving this message.

The only unusual thing about my IMAP account is that its SSL cert doesn't match its address. That is, the cert was issued to my ISP, but I have to contact it at my own domain. Most mail clients simply give me a warning; to get around that warning I've created an etc/hosts entry, but using that address instead of the usual one doesn't seem to help the problem.

Any idea what's going on?