Today I ran into a problem that was very unique. We had one user, with a brand new iPhone, that was unable to successfully add their Exchange Activesync mailbox to their iPhone (this would apply to android as well). The account would add to the phone, but when they would open the mail app and refresh, they would just get an error message that said “Unable to get mail.” We could add any other users mailbox to the phone and it would work perfectly. It ended up having to do with some of the security groups they were a member of, but more importantly, Inheritance had been disabled on their Active Directory account. We are running Exchange 2013, but I’ve seen this issue apply to Exchange 2010 and other versions as well.
Like I said, we could add the account, but when trying to refresh mail on the phone, we got this nice popup box on the iPhone.
To troubleshoot further, I went to http://www.testexchangeconnectivity.com to see if I could get some more details. Come to find out, the server was kicking back the following: “Exchange ActiveSync returned an HTTP 500 response (Internal Server Error). Only on that one specific user account did we get this error. Any and every other account worked perfectly. After some digging and troubleshooting, we found a fix.