MyQ App Login Problems
Looks like the original March, 2023 post with the same title from Dewey225 has been locked...
https://discussions.apple.com/thread/254740193
I had a similar issue... I could not log in to the MyQ app (iPhone running IOS 16.7). I'd just get prompted to try again. I removed the app and reinstalled several times. It was so frustrating, especially since I could log into the MyQ app on an old Android and an old iPhone 6s (IOS 15.7.9) successfully.
The fix for me was to turn off "Block All Cookies" in Safari (Settings > Safari > Block All Cookies).
After I successfully logged in to MyQ, I went back and returned the setting to "Block All Cookies". The MyQ app continued working.
Hopefully this will help others as I was unsuccessful finding a solution on the web.