Hello peerrj1034,

Thank you for contacting Mozilla Support and testing the beta version of Firefox. Can you see if the browser has the same behavior under Safe mode? Please see the following article.

Diagnose Firefox issues using Troubleshoot Mode

Please let us know if Youtube works under safe mode.

Cheers, Patrick

Hi,Patrickmc

Same Issue with Safe Mode. I cleared Cache And Everythings . But Same Issue. Any video Play for 1 Sec Only

Peer