Exchange 2013 SP1. Since last week we have the issue that some users are getting an HTTP 500 Internal Server error when they access OWA from the internet after logging on. For other users it works fine. When the users who are having problems access OWA from internally they can logon fine. OWA authentication is set to Windows Integrated.
For external access OWA is published using TMG. No errors are reported in the eventlog of TMG or the Exchange server. Any idea what might cause this? Is there a way to get some more detailed information about the HTTP error 500?
I've checked the issue with inheritance on the AD user object, but the userobjects have inheritance enabled. Also, since it's Exchange 2013 it doesn't have the Form based authentication service which also might cause this error.
Any idea?
Frank.