Endless loop login > you've been logged in > login ... After installing Adobe Account Access

Attempting to update my Create Cloud apps on a spare computer, I get You need to login, followed by the login screen, followed by a browser login window which immediately says "you are now logged in, you can dismiss this window" followed by the login popup again, followed by another browser window, ad infinitum.

This started happening right after I installed Adobe Account Access on my iPhone.

It also started right after I upgraded the spare machine to iOS Big Sur 11.1.  (The first machine I upgraded to 11.1 seemed to go OK, so I thought I was safe.)

Complete uninstall followed by attempt to reinstall runs into the same issues.

Any remedies?