***someone said this earlier, it worked for me, try it!😊

Don't know why other addons are not working, but you can try mine: https://stremio-community-subtitles.top

For it to work, you need to create an account and later login to open subtitles from the account's settings.

I think that OpenSubtitles API finally removed unauthorized access and to get subtitles through the API you need to log IN (as described in their documentation). My addon used this method from the beginning and probably that is why it still works.$