Thank you for your reply, dr 
Yes, they can handle that much
Yes, I purchased the Pro version yesterday (at 50% off) and have the license on my eLicenser. Both machines have the current version 4.0.42.240 (Public Beta). Under the “VST Cloud” menu in Nuendo (Version 10.2.10 Build 301) there are two items, “VST Connect PRO” and “VST Connect SE”. Under “VST Connect PRO” I select “Create VST Connect”
My desktop PC running Win10 Pro (Where I’m running Nuendo 10 and VST Connect PRO) is connected to the router via hard-wired ethernet cable but the MacBook Air running High Sierra 10.13.6 is connected to the same router via WiFi. Could that be the issue? There is no way to hard-wire the MacBook Air. I have also tried connecting with a KEY and I have also tried connecting with both machines logging in with unique MySteingberg credentials. Logging in with a KEY brings up an error message on the MacBook Air which says “Sorry, you cannot=== not connect within your local network. Make sure both sides use the same and up-to-date version!”. When trying to connect by logging in with unique MySteinberg credentials on each machine, I can see the respective user names on the opposite machines, I get the dreaded “Somebody tries to connect to you from within your local network. This is not supported.” message.
For now, I’m going to hold off on the 4G HotrSpot connection in the hopes that an answer may show up on this thread.
Thank you very much again for your reply