MyChevrolet App No Longer Works

JSW (and anyone else who might be experiencing this problem), after several contacts with OnStar which didn't resolve the issue, here's what I finally did to solve--hopefully permanently--the problem.

I uninstalled the app from my phone (Pixel 6), and I installed it on an old android phone that I had laying around in a junk drawer. (This phone had no SIM card and therefore no cellular service, but I could still use it on my WIFI.)  I intalled the MyChevrolet app on this old phone, logged in, and everything seemed to work correctly. Then, I uninstalled the app on that phone, and reinstalled it on my current (Pixel 6) phone. Inexplicably, that worked! I no longer got stuck on the PIN screen!

I've been using the app on a regular basis for well over a month now without having the problem recur.  I hope this helps JSW and anyone else who might be having the "stuck-on-PIN-screen" problem. Good luck!