Forticlient not woking for MacOS- OK with windows ?server issue

Our hospital has just started using Fortinet VPN.

I have tried installing FortiClient on 3 different Macs (High Sierra, Mojave and Catalina) and also using iOS. Each time, after entering the Fortitoken, I get a "VPN connected" with an IP address and bytes sent and received. However, I can not logon to a remote server (or ping it).

If on the same Mac, I open up a windows virtual machine and use FortiClient, then all works no problem.

Is there some server setting in the hospital that needs to allow other OS access, apart from windows. I have asked the IT dept, but the answer so far is "refer to Fortinet documentation as we don't have Macs."

Thanks