I am using Outlook 2003, with Exchange 2003 (Windows SBS 2003), I have one user that cannot use Exchange with Outlook. Whenever I setup his Exchange profile in any Outlook 2003 client I get the following message - "Unable to open your default e-mail folders. The Microsoft Exchange Server computer is not available. Either there are network problems or the Microsoft Exchange Server computer is down for maintenance."
I can setup other users on the same computer that I am having problems on without any problems. I tried setting the problem user account up on another computer and am getting the same error. I can use the Outlook WebAccess without any problems, logged in with the problem user account. I can ping the exchange server by name or IP, I can access shared folders off of the Exchange server without any problem as well. I have performed a repair on Office, I have completely removed and reinstalled Office, I have removed all Outlook profiles and recreated them. I am not using roaming profiles. I am not experiencing any other problems with this users account. I can even setup a different users email box while logged in as the problem user and after authenticating with Exchange as the different user it works fine. I would assume a problem with the Exchange mailbox, corrupt mailbox or something, but it can be accessed via Webmail without any problems.