All the mountains of advice to do this/that I've gotten from TT help has been a worthless waste of time. Even working with an agent for an hour didn't help.
I was able to track the problem down myself. Many years ago, after getting my new laptop, I tried setting up Ethernet, but had so many problems I abandoned it and eliminated the cables and have used WiFi with no problem whatsoever for the past many years. Unfortunately, the Ethernet adapter was still "available" in the system in the Network center. And what does TT do? It tries to use that adapter! When I launch TT program to activate it, the first message I get is that I can't connect to the internet, while at the same time I'm connected to the TT web site using WiFi. So I disabled the adapter, and everything worked fine.
This must be some sort of bug in TT, to use an unavailable internet port rather than the available WiFi.
