How to fix RDP connection error on Windows server2016?

Question

RDP

Good afternoon!
The situation is the following. There is a Windows server 2016 domain controller, a VPN was raised, the distribution of rights was done, everything worked properly, that is, people connected everything well from home, the other day, out of 50 people, 7 could not connect via RDP, everyone had the same error: " Insufficient rights to connect to remote desktop."
I looked at the rights to users in AD, they stand as usual:
-Domain users
-Remote desktop users
If you add "Domain Administrator" to the user - then it allows you to remotely - but this is not an option.
also created a new account, issued the same rights:
"Domain Users"
"Remote Desktop Users".
does not start up the same error
Clients all with Win10.