RDP fails over a Windows VPN

Using Windows 10, trying to RDP to Win2008 Server. 
When on a static IP, I can connect.
When on a VPN, set up through Windows, I cannot connect to the server.

I can Ping the server, but not Telnet on 3389 to the server, or RDP to its IP address (or its name)
Colleagues are able to RDP to the server, using same VPN set up.

Have tried turning off Windows Defender Firewall, without any success.
Maybe I need to add the IP address to the Hosts configuration ?

I know there are lots of questions about RDP over VPN, I am struggling to find a match to my situation.

Hoping someone can help!