So i have been having an issue with Firefox and Facebook for around one to two weeks now. Problem is only with certain ( but normally different) content of videos not playing, they show up the starting load video with a "play button" shown, but cant actually start the video itself. I have tried multiple solutions already, from reinstalling Adobe Flash Player, updating Firefox, starting firefox in safe mode and turning off hardware acceleration, nothing has helped me. I tried watching same videos that i am having issue with at Firefox over with Microsoft Edge and there was not a single problem as all played fine, so i am really wondering what could possibly be wrong?

Youtube and rest of videos works completely fine and the only issue i find is with certain but not all videos on Facebook, as some load normally and some dont, even from the same author of videos.