RDP 8.0 / Remote Gateway

After updaing machines with RDP 8, remote connections to the remote desktop gateway fail, the login screen appears, but the user cannot get past this, when running RDP 7.1 or below, there is no issue.

Remote Desktop Gateway server is Windows 2008R2 64bit SP1, latest updates.  Clients are Windows 7 Pro SP1, latest updates.

Thanks
Mark