Videos don't play on SOME sites?

Hi, Sorry to hear that. Here are some standard troubleshooting steps that may resolve the issue: # Please check if you have [[Enhanced Tracking Protection in Firefox for desktop|Enhanced Tracking Protection]] (ETP) enabled. You can do that by clicking the shield [[Image:Fx89ShieldIcon]] icon in the left part of the address bar. #* If ETP is enabled, try disabling it. # If the problem is not fixed, try [[How to clear the Firefox cache|clearing Firefox cache]]. # If it does not help, try [[Clear cookies and site data in Firefox|clearing cookies and data]] for the website you experience troubles with (''warning: you will be logged out on this website''). # If it also does not help, try [[Diagnose Firefox issues using Troubleshoot Mode|running Firefox in Troubleshoot Mode]]. If the problem doesn't persist, please follow the steps from [[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems | this article]] to troubleshoot further. # If nothing from the above helps, try [[Manage Firefox profiles|creating a new Firefox profile]] and check if the issue persists there. If it doesn't, you can [[Restore bookmarks, passwords and data from an old Firefox profile|start copying files from your old profile to the new one]] to identify which one causes the issue. See [[About your important data and their files|this article]] on what files to copy. Does any of the above help? Looking forward to your update on how it goes!