Show the issue and provide links for us to replicate. What version of Firefox? What do you see here. see screenshot Also try reset to see if it helps.

https://www.123greetings.com/birthday/happy_birthday/happy_birthday_with_a_cute_band_.html .All the sites are like this. Today Microsoft reinstalled win. 11 but I still have no sound. i use Mozilla Firefox. Your screen shot shows reset sound device. mine does not show same.

Yes, the happy birthday song works for me. This is a Windows issue. Try going into device management and update or remove the driver for your sound device. Then reboot windows. https://www.google.com/search?client=firefox-b-1-d&q=device+management+and+update+or+remove+the+driver+for+your+sound+device

Been to the sound driver. I have the best installed was told.

do you think it could be the media player?

I don't have any sound I played sound once on 123greatings now it won't play.