first things first, i did come across old solutions and they did NOT work. '''turning off hardware acceleration did not fix my issue. the videos will not play in safe mode, and they will not play with firefox "refreshed" or with all addons off.''' ive had this happen numerous times over and it kind of just randomly stops, but i never know how long itll last. its happened again today, where videos on youtube, tumblr, twitter, etc will not play. its like its at the very start of the video and just wont play. it seems my firefox just updated today too, but i cant say this has only happened when i update so idk what the cause is. if it is update related i dont know how to fix it.