> I managed to have it work again! [...] I opened the Scripts Window in OWB and
> I deleted all the scripts, then I added all the scripts again and checked enable
> and now it works. [...] I could play them [...], but I could not do a full screen

Sounds like this problem I had myself:

https://morph.zone/modules/newbb_plus/viewtopic.php?forum=3&topic_id=9462&start=119

>> Put simply, OWB cannot play Youtube videos in any other way than via HTML5.

> I'm not sure that it is right that OWB can not play Youtube videos [...].
> [...] So if OWB can't play them

Nobody said that OWB could not play Youtube videos.

> [...] and Flash plugin is disabled, what played them then?

OWB via HTML5, as I said.