Firefox doesn't play Youtube videos. When opening Youtube website, the loading progress bar stops at around 80% and the video keeps showing the loading circle when pressing 'play' button. Seems like only the tabs that have been opened for a while are affected. When opening the same video in the new tab, the issue is gone. When the app is force stopped and started again, the issue disappears and then appears again after some time. Installed add-ons: uBlock Origin Privacy Badger Video Background Play Fix The issue persists when all add-ons are disabled. Can be reproduced when using a mobile network without a VPN connection. I haven't tried to reproduce the issue with all the add-ons initially disabled. I've found similar issues, that are however not limited to Youtube: https://support.mozilla.org/en-US/questions/1411513 https://support.mozilla.org/en-US/questions/1419131 https://support.mozilla.org/en-US/questions/1374967 This issue is focused on Youtube, so that hopefully it will be easier to debug. Thank you for developing and contributing to Firefox for Android. It's a modern and competitive mobile browser. I appreciate your effort!