I am running Outlook 2003 SP1 on Windows XP SP2.
We are running Exchange 2003 on Windows Server 2003.
When I am logged on at work, Outlook connects to Exchange without problems.

BUT: When my PC is connected to the same network by SSL VPN (Citrix Access
Gateway) from the outside, Outlook tries to connect, but gives up and stays
disconnected; when it's trying to send and fetch mail, I get the 0x8004011D
error message that Exchange is not available. Automatic or manual logon to
Exchange makes no difference.

This was not a problem initially. For a long time I could connect to
Exchange by the same SSL VPN, but then - some weeks ago - the problem arose.

I can ping the server where Exchange resides. I can map to and operate on
the file areas of the same server, and connect to the server by remote
desktop. I can connect to Exchange by OWA without problems.

Any suggestions how to limit the range of possible solutions?