I could previously login to OSM on mobile and also through CoMaps. After uninstalling and reinstalling CoMaps a couple of times due to configuration issues, I could no longer login either through CoMaps or even on a mobile browser (Brave or Firefox). I kept getting a message that I was unable to login using those credentials. I ended up clicking the “Sign Up” link instead, using the same email and password, getting a new authentication link, and then was able to login. OSM did lose all records of my map edits, though. Thought this might help someone.
Edit: I seem to now have two different accounts with the same email and display name. Checking OAuth 2 Authorizations on desktop shows the old tokens and has my edits, while on mobile there are only OAuth Authorizations from today and 0 edits.