Try 140.4.0 ESR as a work around to give them time to figure out what they broke unless you depend on a feature in 144. [1] Works for me on Linux and Windows. Or try starting 144 in safe mode to disable all addons as a test.
[1] - https://ftp.mozilla.org/pub/firefox/releases/140.4.0esr/
I signed out, flushed all data, disabled all extension but it did not help.
Incognito mode works though..
Hmm.. in normal mode, I see that https://rr5---sn-t0a7ln7d.googlevideo.com is called but gets ns_error_unknown_host but in incognito mode rr5 is not called and all works. Changing to dns over https did not help. But I heard about the AWS outage today and that it has something to do with DNS so i think there's the issue. Though am not sure why incognito works.
The only other thing I could suggest is use the web console network tab to see what requests may be hanging or timing out when not in Incognito mode.
Yes, this issue is real and affecting many Firefox users — YouTube videos show a black screen or error message, while working fine in Chrome. It’s not adblock-related, and likely tied to how YouTube’s new player interacts with Firefox’s rendering engine.
What’s Happening
YouTube’s new player rollout seems to be causing playback failures in Firefox.
Users report:
Black screen or “An error occurred” message
Videos not loading at all
UI glitches on mobile and desktop
Chrome-based browsers (Brave, Edge, etc.) work fine — suggesting a compatibility issue, not a network or account problem.
What You Can Try
Clear Firefox cache and cookies
Corrupted data can block video rendering.
Disable hardware acceleration
Go to Settings > General > Performance and uncheck “Use recommended performance settings.”
Try Firefox in Safe Mode
Launch with extensions disabled to rule out conflicts.
Switch to YouTube’s mobile site temporarily
Use m.youtube.com — it often bypasses player issues.Use an alternate browser until fixed
Chrome, Brave, or Edge are working normally.
Only the incognito mode works, nothing else. Makes no sense to me. It's the second day now. Not sure if I should be angry with Google(likely) or Firefox for this. The main problem seems to be that some googlevideo.com subdomains are returning 403 errors. Strange thing is that in normal mode, the rr5 subdomain is called and returns the 403 but in incognito mode rr3 is called and that returns content just fine. I have no clue what picks the subdomains from which the videos are streamed.
I figured it out. I must have gotten banned by youtube, despite me having no youtube channel, so i cannot like or comment videos. Hence I could have not "behaved badly" by any means. I opened the incognito mode, where videos work, i signed in and then instantly videos don't play. I have youtube account solely to be able to follow channels and have a subscription feed as well as history for recommendations.
This is the weirdest thing I have ever experienced with youtube.
PS: and obviously this is the same with chrome-based browsers. It is my account that is the issue.
After three days it is working again. Seriously, youtube engineering seems to be going the Amazon way.
Works for me on Firefox for Android with version 143.0.4. And I just updated to 144.0 and tried again, and that is working also.
Phone is not a problem, desktop is.
Just had a chance to try version 144.0 for desktop on Windows, and that's working for me also.
I also have problems with Firefox. I guess it is something Google related...