Thank you for your response/support/encouragement, @SteamTrain .
I just spent 30 minutes with TT tech support.
Blaming your video drivers is the first excuse, and then its your firewall, and then let's try uninstall-reboot-reinstall because "it might be a Windows 10 problem."
The "800x600, 100% scaling and click around and try to paste and cross your fingers until it works" is the official fix.
...and TT has no clue why.
Good luck to all!
