I had a problem a few days ago, not with video, but podcast on another website. The player did not react in any way, when I clicked the playbutton.
I contacted the site since there has never been a problem there. The answer was quite surprising. They told me that browsers are very often updated and not tested well, so various problems occur at various times. I changed from Chrome to Firefox and then it played without problems.
Strange things we have to think of but might be worth a try