You need your firewall to let TCP / UDP
443 / 80 / 3389
ports opened for ingoing and outgoing traffic.
These are the IP addresses to open at the level of software and hardware firewalls:
220.127.116.11 : License / telemetry
18.104.22.168 : Updates
22.214.171.124 : TSplus compatibility updates / Check for updates / View changelog
These are the URLs to allow for updates: