Issue: If a user is starting an RDP relay session to connect to a Windows server 2012 computer and has the remote desktop client version 8.0 or higher, the session fails to connect.
Workaround: To workaround this issue, users can use Windows 7 or earlier version with mstsc version 6.1.7601 or earlier. If Windows 7 is updated to use latest version of RDP, you can downgrade to lower version by uninstalling the patch KB 2592687. This is an optional update for Windows 7 and Windows Server 2008 R2 to update RDP protocol version.