Sketchup 2021 on Research Machines Network - Unable to connect to network licence server

Installed Sketchup 2021 on school network (Research Machines). RM have said they’ve opened up the Ports 5053 and 50530 . I’ve also tried changing “OnlineTestURL” in Private Preferences.json to a reliable site. Attempted to Add a classic licence and it replies with ::

Sketchup Pro is unable to connect to the network license server,

Anybody else had the same issue?

Update - now working after our service provider made some changes.

"On checking, the firewall log, I could see that some amazon traffic passing through the firewall as part of

So I have added some Amazon IP ranges to the existing firewall rule."

The software now conncts to the server when adding the licence