What could be the problem when connecting via rdp via a 3G modem?

Question

Windows

Actually a subject. I can not connect via rdp to one virtual server via a 3g modem. And only through him. Through a regular adsl at work, a home provider's ezernet, to another virtual server on the same network - everything is fine.
Details. There is a server on which several virtual machines with Server 2008 R2 are spinning. White external address, Internet via adsl modem and router. I connect to different servers through port forwarding. No problems, everything works. About two weeks ago I decided to take up security and on one of the servers in the RDP settings I changed the security level to SSl and the encryption level to FIPS-compliant. Again, no problems, everything works. Until I tried to connect via a 3G modem. I repeat - changes were made only on one server.
At first it did not connect with the error "licensing timed out". Googling showed many solutions, but nothing helped me. I decided to just take down the terminal server along with the licenses and reconfigure it. Now it just doesn't connect with an error, the server is not responding, although the connection is starting to be established.
Everything connects to other servers via 3G and from other places to the problem server without any problems. The problem is only when connecting via 3Gmodem to a specific server. I didn't find anything suspicious in the logs. I suspect something with licensing, but what?

Answer 1

I think the problem is simple. The quality of 3GG communication in ... opera. Or the channel is clogged with all sorts of crap. It is not clear what kind of router, what kind of whistle and whether there is an AD.