[2021] How to connect to the server (War Thunder)

It's not an server issue.

Please re-read his post.

He got no issue to log in on GeForce Now.

Have you checked your A-V settings?

Anti-Virus software (or more specific in this case - firewall).

Do you see hangar? Or game hangs before it load?

What's your PC spec?

Looks like game cannot load hangar and hangs.