I’ve had this happen when trying to use a password longer than 60 characters. I could set it just fine through registration or password reset, but I could not log in with it. Limiting the length of my password to 60 characters resolved the issue.

I keep my keys on a Yubikey. I’ve not really had a need to use the GPG portion of this on Android, but it works fine on Linux and MacOS.

I used this guide: https://github.com/drduh/YubiKey-Guide

They would show for others on your instance, but not for people on other instances, so each instance will have a separate downvote counter.