We've been using Outlook 2003 to access our corp Exchange server over a VPN for years. Yesterday, all of our remote clients began having the same problem: On starting Outlook it takes a LONG time before the program splash screen goes away, then they get the message in the lower right status bar area: Trying to connect... and it never does.
The Exchange Server is fine and so are the email accounts. I know this because I can remote desktop into my office PC, start the same version of Outlook on that PC and it all works fine. No one on the internal LAN is having any trouble. I can also ping the Exchange Server over the VPN by its network name and it resolves to its IP address and responds just fine. When I thought this was simply a one-client problem, I recreated my Outlook profile because I know these get corrupted from time to time but that didn't fix it of course. I also tried an Office repair using the installer and that didn't help either.
More about our configuration: We have a single domain in a small office environment running a single Windows 2003 Server. This same server is also the domain controller, Exchange Server, and remote access server. The office LAN is connected to the Internet over a DSL Router, which has the appropriate service pass throughs to allow the VPNs to connect to the remote access server. The ISP for the office and for all remote clients is ATT, but in totally different geographical locations. I have tried swapping the DSL Router (we have two spares configured and ready to go), but that had no effect on the problem. Ideas???