I had to re-install my Zimbra Collaboration Suite version 4.0.2 to fix some corruptions in the software.
Prior to re-installing, I was able to see all the messages in my zimbra user mailbox using Outlook with an IMAP connection.
Since I re-installed, I cannot see any messages in my zimbra user mailbox. It connects just fine but it shows it as empty. If I logon to my zimbra mailbox (Tomcat) I see the content of my inbox but not with Outlook.
Everything else works fine.