Problem

I cannot connect to our exchange server using IMAP. We we using Exchange 2003. It has had IMAP enabled, the firewall has been configured to port forward port 143 and the user's account have had IMAP enabled.

I've attempted IMAP connections for this user from the phone system, from Outlook, and from Thunderbird.  All have the same result; the connection is refused.

The user's account name is "john".  The user object name is "John Smith".  I've tried a variety of combinations including "johns", "mydomain/johns", "mydomain/johns/John Smith", and several others that don't come immediately to mind.

Resolution

It should be DOMAIN/User/ALIAS - not display name.

In the user account, have a look for the Exchange Alias (on one of the Exchange tabs) that should be the last item in the full username.

This is only a problem because that account has been renamed at some point (presumably)

For example, the account name may be John, but the alias is JohnS - you would try:

ABCCOMPANY/john/johns

Alternatively, (if possible) change the alias to be the same as the account name.