Works for me. see screenshot Show the issue, what are you getting when trying to play. What troubleshooting steps have you tried? Did you clear the browser cache? Did you try Firefox in Safe Mode? Did you try Firefox under a different windows account? What security software are you running? Sorry for the rapid fire questions, but just got back from the gym.  ;-))

I have tried all the suggestions here. I cleared the cache, tried safe mode etc. I never had an issue until Firefox did an update. I haven't changed any security software. YouTube works fine with other browsers so the issue has to be with the recent update. I use Webroot secure.

Disable Webroot, reboot, and try again.

Same issue.

Are you able to record your desktop and post a video on YouTube? I use OBS to record. It will help us help you if we can see the issue.

Have never used that before.

https://youtu.be/ZJFaOpAwCjY

Hope this works.

https://youtu.be/aNP8P9uLMDA

Another try

Can't seem to post it as a video.

https://www.youtube.com/shorts/NHpnjHPr2z8 The video works for me. see screenshot

Thanks for the video. This is a shot in the dark, but who are you using for DNS? Can you clear you dns cache and try a different provider like 1.1.1.1 / 1.0.0.1 just to see if you makes a difference.

My Firefox is completely messed up. Keep getting message that Firefox is not responding and asking me to close the program. I tried to re-install it and same thing happens.

I just saw a message that says the latest Firefox is not compatible with Webroot Secure.

How about a refresh of Firefox? https://support.mozilla.org/en-US/kb/reset-preferences-fix-problems

The temporarysolution was to have Webroot setting for Firefox to be set to "Allow" instead of "protect". This is no longer working.

Good old Webroot...

Thanks to all who helped.

YouTube videos don't work with Firefox. There is no support with Firefox. YouTube works on all other browsers so the problem definitely lies with Firefox.