Users using Windows 8, 8.1 or Windows 10 can't connect to the RD Gateway with the error "Your computer can't connect to the remote computer because the Remote Desktop Gateway server is temporarily unavailable".
Caused by update KB2592687, an update to the RDP Client 8.0
Push out a registry fix to all Windows 8, 8.1 or 10 clients. (Tip: Use Group Policy Preferences)
HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client
REG_DWORD RDGClientTransport (1)