Licence Server/Passolo clients on different network domains. Can't get a licence.

Hi,
Can a Passolo installation on a PC on network domain "A" get a licence from a License Server on network domain "B"?
After a new install, I keep getting the error:
"Cannot retrieve licence from the specific server. Check that the licence server has a valid licence for this application, or run Studio as administrator again to specify the licence server name".

I've tried specifying the server name with/without domain and get the same error each time.
The PC can see the Licence Server (can even login via RDP).

Other machines happily get licences from the Licence Server, but they are all on the same domain as the Licence Server.
Regards
Mark