Some, but not all, videos on Twitter and tumblr don't function. On tumblr, the audio usually plays but the video is blank. On Twitter, the videos are always stuck loading. Thumbnails always load, there is no way for me to know if a video will work or not without trying to play it. They work when I use a different browser, and Youtube is fully functional, so it can't be an issue with my laptop. The other person in the house who uses Firefox is able to play the same videos without issue. I've searched for solutions and exhausted the possibilities in dozens of articles and support sites saying the same things over and over again. I'm at my wit's end. I've tried: -disabling hardware acceleration -audio and video permissions -clearing cache and cookies -disabling enhanced tracking protection -switching off adblocker -running it in troubleshooting mode -refreshing Firefox None of these did anything. Can anybody give me even a scrap of an idea as to what I can do?