I am running MS Exchange 2003 SP2 on a Windows 2000 SP4 server. All of the sudden after years of working fine the OWA stops working today. When I try to access it I get the login prompt but after entering the correct credentials I get a "page cannot be displayed" error. This is only happening from external sites. I have accessed the OWA page from within the LAN and was able to login fine. I have checked with the company that manages the firewall and they assured me they have been no changes made there and everything looks good on that end. No changes to the server that I am aware of. I suspect maybe a Windows update screwed it up but I honestly don't know where to start.