I went to a new site today (Lookout) and signed up but FF Android did not save my PW. I tried to solve this on my own but I don't see other questions about this specific issue and the article I did find "Save passwords in Firefox for Android" https://support.mozilla.org/en-US/kb/save-passwords-firefox-android does not solve my issue. I checked my settings and "Remember logins" is already checked.