We have a CAS server running Exchange 2007 on Server 2008 R2 Enterprise that was working fine until today. Nothing should have changed; no updates have been installed, I am the only one who makes administrative changes to this server, etc.
OWA works normally on our internal network. Externally, OWA works as intended with Firefox. With IE 8/9/10 (and I would assume 11), all that happens is IE errors out instantaneously with "Internet Explorer cannot display the webpage".
Any help would be greatly appreciated.