Can you post a link to a publicly accessible page (i.e. no authentication or signing on required)?

This usually means that the media file is not a valid link or Firefox isn't able to play the file for other reasons. You can check the Web Console for media related messages.

• "3-bar" menu button -> Web Developer or Tools -> Browser Tools -> Web Developer Tools
• https://developer.mozilla.org/en-US/docs/Tools/Web_Console

In the web console i get the error:

Media resource file:///{FILEPATH} could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_MEDIASINK_ERR (0x806e000b)
Details: OnMediaSinkAudioError {FILENAME}.mp3

Can I get some help anyone?

And here's all the errors and warnings i get when watching a youtube video:

downloadable font: download failed (font-family: "Roboto" style:normal weight:500 stretch:100 src index:0): status=2152398850 source: https://fonts.gstatic.com/s/roboto/v29/KFOlCnqEu92Fr1MmEU9fABc4EsA.woff2
downloadable font: download failed (font-family: "Roboto" style:normal weight:400 stretch:100 src index:0): status=2152398850 source: https://fonts.gstatic.com/s/roboto/v29/KFOmCnqEu92Fr1Mu5mxKOzY.woff2
Some cookies are misusing the recommended “SameSite“ attribute 4
Failed to get service worker registration(s): Storage access is restricted in this context due to user settings or private browsing mode. desktop_polymer.js:12432:83
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at data:text/plain;base64,Cg==. (Reason: CORS request not http).
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://googleads.g.doubleclick.net/pagead/id. (Reason: CORS request did not succeed).
Will-change memory consumption is too high. Budget limit is the document surface area multiplied by 3 (69115 px). Occurrences of will-change over the budget will be ignored. watch
MouseEvent.mozPressure is deprecated. Use PointerEvent.pressure instead. base.js:1325:347
Source map error: Error: request failed with status 404
Resource URL: https://www.youtube.com/watch?v=jNQXAC9IVRw
Source Map URL: yt-live-chat-default-theme.css.map
Loading failed for the <script> with source “https://static.doubleclick.net/instream/ad_status.js”. watch:1:1
Failed to register/update a ServiceWorker for scope ‘https://www.youtube.com/’: Storage access is restricted in this context due to user settings or private browsing mode. desktop_polymer.js:12459:132
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at data:text/plain;base64,Cg==. (Reason: CORS request not http).
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://googleads.g.doubleclick.net/pagead/id. (Reason: CORS request did not succeed).

I really need help here. No one is responding

I finally found someone with my same problem that kinda hasn't relolved it yet, but maybe they can explain my problem better than i can...

So there is no solution to this yet?

I have the same issue. I just upgraded to Win11 and a new computer. Reinstalled the latest Firefox after dl from the mozilla site.

I usually use a Bose Color Soundlink paired via bluetooth to be my computer speaker. It works. I test it. It is listed as the default, paired speaker for output. It plays system files. It plays mp3s I click on from my hard drive.

But go to YouTube or any other website and click on a video, you get video, no SOUND. At all. Yes, I've made sure the sound slider is all the way up. I have paired and unpaired. The speaker works. Just not with Firefox. As a last test, I opened Microsoft edge. YouTube worked normally.

So, any solutions yet?

Well, I think I fixed the problem. Using the tip to explore permissions, I clicked on the lock icon and gave Firefox permission to USE THE MICROPHONE. I don't actually have a microphone on this computer so that did not occur to me to do. It was a shot in the dark, but I tried it and that seems to have fixed it. Apparently, FF thinks the bluetooth speaker is a microphone. (It has no microphone.)

I have read elsewhere about such an issue being fixed by disabling hardware acceleration. The relevant setting is on the General page of Settings. https://support.mozilla.org/en-US/kb/forum-response-disable-hardware-acceleration

You could also try Troubleshoot Mode. https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode