I can't watch Facebook videos on my Mac

First thing is make sure the computer is running the latest version of Ventura version 13.0.1

Second, is the video download to the computer ? If so use the Builtin QuickTime Player application located in in the Outer Folder of Launchpad or search Quicktime in Search of Finder

Thirdly, if above does not work communicate with FaceBook as per link provided Help Center - Facebookhttps://www.facebook.com › help

I suggest you close the app and try again. If the error continues it will reset the computer. As a last resort, I recommend updating the system. The new version should fix the bugs

Are you having problems with all Facebook videos or just the ones on the page you are following? Which browser are you using and have you tried others?

How it works within the FB Application ( Environment ) on an iDevice does not always translate to working outside of the FB Application (Environment )

It's hard to say what the problem might be without knowing which page is causing the problem. If you have any Safari extensions installed to block ads etc. you can trying disabling them and test.