According to your description, it sounds like the Connection broker no response.
Is this a server with all RDS roles all in one?
Have you tried to reinstall Connection broker?
Hope this helps and please help to accept as Answer if the response is useful.
Server Admin can't manage Remote Desktop deployment
I've a test Remote Desktop deployment that is failing to be managed via Server Admin. Collections and deployment overview never stops refreshing, but nothing is shown:
When I try to edit deployment details, another error shows:
Everything is working properly from users side, as they can connect and work. I also can manage all deployment details and even create new applications through PowerShell and New-RDRemoteApp command, but the only failing related command is Get-RDUserSession.
I see nothing strange in event logs that may give a clue, so any help is very welcome.