Some videos don't play on Firefox

Bugs
1

ex. https://www.youtube.com/watch?v=vFMuUUoVaZE

This video plays normally on Google Chrome but not on Firefox

2

What happens if you try to play it in Firefox. Do you see any error messages?

3

I get the message:

Video Unavailable
Watch on YouTube

4

Does it work when you open anonymous window in Firefox?