Trying to use a Windows 10 device to stream Apple TV - caught in endless loop..

I created an account, added a valid credit card, but when I go to tv.apple.com and try to sign in to get the streaming service, I get this message "Before you can sign in on the web, first sign in to the Apple TV app on your iPhone or iPad. On a computer, sign in to Apple TV or iTunes." I have already signed into apple.com/tv, it shows me signed in, but it won't let me use the same logon at tv.apple.com to sign into AppleTV+ and pay for the streaming service. Why does this not work? I even tried resetting my PW once, just to see if that would help, no dice. What is the issue?