As per the title... If I access "mail.yahoo.com" (specifically the site in the screenshot) at all in a Firefox session, that session is no longer able to play videos, i.e. Youtube, Tiktok, or any other streaming videos. The videos "break" in that the player loads, but the content does not load, and the player is stuck endlessly with the loading circle animation. Video previews also don't play when mousing over the thumbnails. This is solved only by restarting Firefox, i.e. in a totally new session. It cannot be circumvented by opening a Private Browsing session, or new window, or closing the Yahoo Mail tab. This bug is reproducible in a new profile: i.e. I went to about:profiles, loaded a new profile and opened browser in that new profile, went to mail.yahoo.com in one tab, opened youtube.com in another tab, and none of the videos (or ads) played in that youtube tab. This bug is reproducible in troubleshoot mode. This bug does not occur in a different browser, e.g. Brave. This bug only seems to have happened recently, possibly with one of the recent updates. Edit: I rolled back to 143.0.4 and it still occurs. OS: Win10 Home 22H2 19045.6456 Firefox: 144.0.2 64bit Extensions: Clickbait Remover for Youtube Google (verbatim) search NoGoogleAi Old Reddit Redirect Ublock origin Video DownloadHelper Youtube Anti-translate I pressed "Share Data" for the troubleshooting information but it's not appearing in the question... not sure if I should paste that wall of text...