Unable to connect to server from vpn/home office

We have permanent license for VC Essentials 4.5 with floating license on server 2.10. We are able to connect to server and work on it but only within our workplace building where server is. If anyone tries to use VPN, or connect to it outside our workplace we get an error. Situation repeats for all pc/laptops.
There is nothing about it in 2.10 license instruction.

Maybe the VPN is blocking the messages sent to the server. I suggest contacting technical support.