Failed to connect to the IMAP server.

Hi. I'm trying to setup and test IMAP settings for Support System.

I'm getting the Failed to connect to the IMAP server. Error.

I've got email accnt set up on same server same domain that wpmu is installed on. I'm on a Plesk 10 server. Set up the email account, logged into webmail, turned on IMAP in the email settings.

Tried using SSL yes and no,
Tried IMAP username both full and partial. like username and username@domain.com
Default IMAP port 992.

Any ideas?