After the logon in the OWA of Exchange Server 2010, the “Website can not display the page” error is returned. Also, the OWA error HTTP 500 code is returned:
In environments that uses TMG for OWA’s publishing, the error is HTTP 502:
This problem occurs because OWA uses Forms-based authentication to authenticate users, if the Microsoft Exchange Forms-Based Authentication Service is not running, OWA cannot perform authentication.
Simply perform the Microsoft Exchange Forms-Based Authentication Service service start and the problem is resolved.