Well, what video exactly? My 1st guess would always be: your CPU is too slow for the selected video quality/codec.

I've tried https://www.youtube.com/tv#/watch?v=t0Q2otsqC4I and https://www.youtube.com/tv#/watch?v=GVqjpcvKfHY with the User Agent you pasted above and it's working just fine.

[ Edited by jacadcaps 09.02.2022 - 18:44 ]