Comments by Member 4424465 (Top 1 by date)

- Also Doing the below may Help:
- Check the Application Pool of the Service is still running, case point password changed on identity, will shut it down and that would return 500.

- After you have debugged this as others have suggested. You can also put register an Exception Filter to handle unhandled exceptions and just check the server's log, include the stack trace and message
details:
http://www.asp.net/web-api/overview/error-handling/exception-handling