I had two databases which were acting funky.. I created two new databases and migrated all the mailboxes.. deleted the old databases.
The users who were on those databases are now complaining that they (intermittently, not always) type in their user/pass in OWA, but they get a Error 500 when they are redirected to the auth.owa page. With their credentials, I'm able to duplicate the problem.. sometimes.
I've verified that the problem exists on both of our load-balanced CAS servers. It doesn't matter which DAG member is hosting these new databases. I even took one user and migrated him to another database (one that has been in existence for a long time). He still experiences the problem.
Any ideas? I'm on Exchange 2013 SP1