I have been having a kind of a strange issue for a longe while and finally got around to troubleshooting and figuring out why so here is a breakdown of the strange case of the failed remote desktop gateway connection.
The setup is as follow, using diffrent machines Windows 10, 8.1 and 7 to connect to diffrent remote desktop gateway solutions and for some reason the connection failed with wrong username and password to a couple of the RDGWs.
So after som digging and alot of help from my good friend over at isloation.se we found the issue and how to check if you are also running into this issue.
On the RDGW check under incomming connections/monitoring and if the connections display as RPC-HTTP. This is the clue that something is not all right.
So over the years the has been alot of fixes and version of the RDP client for each version of Windows. In the later release support was introduced for RDP over HTTP with UDP as a performance booster. However due to bugs and other things happening there have been posts and information about setting a registry value to make RDP work again. The value is called RDGClientTransport. It is a DWORD and you set it to 1 to get everyting working again.
However what this does is force the RDP client to fall back to RPC-HTTP connections instead of HTTP/UDP. This in turn can cause connection issues if you have modern solutions.
Depsite several blogs and forum posts saying this the value should be 1 you really should change the default value of 0.
So here is the full path to set the value.
HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\RDPClientTransport
As you probably noted it is a current user setting and since I am very lazy. Most of my configuration is done through either Configuration Manager or GPO so in this case it was a GPO setting the value to 1 for all my users. Hence the problem was only on my devices and not my coworkers devices.