In the process of migrating from Exchange 2003 to Exchange 2010 and ForeFront TMG 2010. External users go to OWA login page (format: mailserver.xyzcompany.com) and authenticate. Login window is standard OWA FBA window and says "Secured by ForeFront" at the bottom. Wildcard certificate from external authority has been installed on Exchange 2010 server and imported to ForeFront TMG 2010.
One of two things happens after users authenticate: A blank OWA page is displayed, but nothing else (no mailbox name, folders, etc.) -- OR -- An Internal Error / Error Code 500 page is displayed.
An error appears if user credentials are invalid, so it appears authentication is actually occurring.
Environment:
Exchange 2003 with production mailboxes. This server holds the usual roles plus public folders, OAB, and connector. It is still handling day-to-day email tasks for users. Server 2003 R2. All traffic to and from this server is routed through an existing Linux firewall.
Exchange 2010 with test mailboxes. Only the Client Access and Hub Transport roles have been installed. Server 2008 R2 Hyper-V VM on Server 2012 host. Exchange 2010 server has been published to ForeFront TMG 2010 according to MS guidelines.
Test accounts on Exchange 2010 were created on Exchange 2003 and moved to Exchange 2010. The plan is to move all of the existing mailboxes, public folders, OAB, etc. from Exchange 2003 to Exchange 2010 once traffic is properly routed through FroreFront TMG.
Thanks in advance for any suggestions.