I was scrolling the news feed in Facebook, then I noticed that almost all videos don't play automatically, so I clicked on them and the screen became wider they load for like 2 sec but then appears again the play button. I don't think its a hardware or drivers problem because everything seems normal in Chrome and brave. I noticed that everytime I scroll to a video a small chain appear in the URL bar I clicked on it in the attached image, then un/check it but nothing change. I tried with the following "solutions" but nothing changed: -Safe mode. -Creating a new Profile. -Uninstalling Firefox and deleting Profiles files then reinstalling it again. I've been using Firefox since 2006 and I just don't wanna change the browser to avoid this problem.