YT videos stop playing on FireFox

[yoco]

Hi! Don't know what's wrong but since today I can't watch any video on Youtube with FF browser. After about 40 seconds of videos playing it simply stops and says "something went wrong. refresh or try again later". I tried disabling every YT extension, uBlock, cleared cookies & cache, but nothing works. Problem still persist. Any idea what could be wrong?

For example this video stops at ~45s, but it plays just fine on Brave browser!

 

[+thexfile Subscriber²]

My firefox plays it just fine. 145.0b6 and SponsorBlock and UBlock are running.

[+Nik Louch Subscriber²]

Sounds like it’s playing the pre-cached aspect that is downloaded on page load but the rest which is streamed just isn’t kicking in. I’m feeling like it’s some sort of streaming network issue

[Nick H. Supervisor]

Something that I noticed - and have been noticing for a while - is that certain sites are really clamping down on VPN. Your video example didn't play for me, and I got a similar issue. After disabling the VPN the video played fine.

[yoco]

Maybe I found the culprit. When I disable User Agent all videos play just fine. I will test this more.

[yoco]

For me it's definitely User Agent. Can anyone try this one, and see if you can play YT videos?

https://webextension.org/listing/useragent-switcher.html

[+Nik Louch Subscriber²]

I mean… I’m not installing random extensions. Anyone else then feel free. But the solution: don’t use that extension. End.

[i_was_here]

On 25/10/2025 at 06:23, Nik Louch said:

I mean… I’m not installing random extensions. Anyone else then feel free. But the solution: don’t use that extension. End.

It's actually a recommended extension on the AMO site:

https://addons.mozilla.org/en-US/firefox/addon/user-agent-string-switcher/

Also you do know what a user agent is, right? There are a ton of similar extensions for changing it. 

[+Nik Louch Subscriber²]

On 25/10/2025 at 19:24, i_was_here said:

It's actually a recommended extension on the AMO site:

https://addons.mozilla.org/en-US/firefox/addon/user-agent-string-switcher/

Also you do know what a user agent is, right? There are a ton of similar extensions for changing it. 

Yes, and?

[Nick H. Supervisor]

On 25/10/2025 at 19:24, i_was_here said:

It's actually a recommended extension on the AMO site:

https://addons.mozilla.org/en-US/firefox/addon/user-agent-string-switcher/

If you read the reviews it looks like you're not the only one having an issue with the extension - multiple reviews over the past few months pointing out that the extension is at best missing previous options, and at worst is completely broken.

[+InsaneNutter MVC]

What are you changing the user agent to? YouTube have been on a bit of a vendetta recently, attempting to block third party video downloading tools / clients.

If I had to guess altering your user agent to something more generic has triggered protections aimed at blocking these video downloading tools.

As a test you could change to the user agent from Edge: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0 and see if the issue persists.

[yoco]

I changed User Agent from Chrome to Vivaldi and is working fine for now. All videos are playing.

But I do have one issue, that's been bugging me for a while now. About 70% of videos when I open them I get message "Experiencing interruptions?" message and video is loading, sometimes just for a second or two, but sometimes it takes like 30 seconds for video to start playing. This is completely random. I do not get this "issue" if I use Chrome or Brave browser. 

[Steven P. Administrators]

I think in Privacy & Security the default setting is now "Strict" which also might be messing with YouTube.

Google has a history of messing with YouTube for Firefox users.

I have mine set to Standard because Strict broke some websites.

[yoco]

I think I might have fixed my problem. Under uBlock Origin custom filters I had one filter enabled, and after disabling that, YT works fine so far