My setup:
Windows server 2012 Standard. I have Hyper-V installed and about 10 vm's. It's been up and running for about 5-6 months with almost no problems.
I have the RD web access setup for people who want to access a vm while working at home. That uses the https://something.something.com/rdweb and work great. I can log as any user and get a random or assigned vm (depending on the user).
I have an off-site office that has a persistent VPN connection to the main office. From the remote office, I can ping their gateway and the main office gateway. I can ping the AD server and any other computer at the main office. So, I know the VPN connection is working (plus I see it working on the router). So, I rule that out as a bad connection.
Typically, the remote office will just type in the computer name to get their vm session running (vm-1, vm-2, vm-3, etc...). Assigned users have a shortcut on their desktop to their respective vm machine.
For the past week, they will just get dropped off. No warning - just lost their connection. They didn't loose the Internet connection. VPN is still running. Can still surf the web on their physical computer. But cannot connect to their vm at the main office. I can ping the vm machine by name or IP and that works. But not RDP to that vm machine.
Everything on my Win 2012 server said RD services are operational. All my remote services are running (remote desktop configuration, remote desktop connection broker, gateway, licensing, management, services). Remember, I can still connect from the outside by going to my https://something.something.com/rdweb and log in as any user and get a vm going.
The remote office will get the "Remote Desktop Gateway Server is Temporarily Unavailable" error. They get that if they try RDP or use the internal web browser address http://servername/rdweb.
When I log into the server and actually go directly to the vm machines from hyper-v, I'll sometimes discover either nothing (i.e. the vm works, I can surf the web and ping whatever, so I know it has network connectivity) or it's totally lost its network connectivity and just can't reach the gateway no matter what. Doing the network repair doesn't solve anything.
And, interestingly enough, when the user tries to load their vm, the remote desktop connection box on the screen will get all the way to saying "loading the virtual machine" but it always fails w/the gateway error message.
So far, my only band-aid solution has been to restart the entire server. Something I wish I didn't have to do. It disrupts more people than helping the 3-4 off-site people.
So, I'm here, seeking help so I can find the root case and get this fixed up.
Any other information you need, please do ask me. I'm very quick to reply back.
Thank you in advance for your help.