Snow Leopard App Store broken
I can no longer download anything not previously purchase from the App Store using Mac OS X 10.6 (Snow Leopard). In particular, I'm trying to download a newer OS, and 10.11/El Capitan is the newest one that will run on my Mac. However, even though all of my payment/billing info is current on my Apple ID, attempting to "Get" El Capitan as shown on this page How to download OS X El Capitan - Apple Support, doesn't work, it gives me an error saying "Software Update Required. To make changes to your payment information, you need to upgrade you mac to the latest version of macOS". I presume this is related to the security changes made to AppleID&App Store on 30-Jun-2018. My login an password are correct, as you can see from my ability to login and post this message.
P.S. I tried setting up an App specific password and using that to login from the App Store, that didn't work either.