[Today’s post comes to us courtesy of Justin Crosby from Commercial Technical Support]
Today we are going to discuss the first thing you should always check if you get an HTTP 500 error attempting to access OWA on an SBS 2011 server, after you have provided your credentials to the login form.
In Exchange 2010 a new service has been introduced to handle forms based authentication (FBA). The service name is Microsoft Exchange Forms-Based Authentication service, MSExchangeFBA for short. If this service is stopped and you have FBA enabled, the default on SBS, you will get an error 500 attempting to access OWA. So if you receive this error please verify that the MSExchangeFBA service is started as your first step.