I recently upgraded to LE 10.0.1 (RPi4.arm).
I also reinstalled the Opensubtitles.org add-on from the Kodi Repository and configured it with my user/password information.
However, when I wanted to download subtitles using this add-on, I got the following error:
"Error searching for subtitles. Your opensubtitles.org username or password is empty or not valid"
I double-checked my credentials by (succefully) logging into the opensubtitles.org site using a browser so I'm quite sure these are working.
I can't find any immediate error in the log-files (attached) but I'm hoping this a known issue and has an easy fix.
Peter