I installed Firefox Flatpak on F38 and some video content is not working. Youtube and Netflix work fine, Prime Video does not. Videos on some website do not play, some give simple error messages wihtout details: NFL.com, tagesschau.de, ran.de and more do also not work.

So, something is wrong but i can not figure out what it is. . Can not figure out if it's in use or not, i guess it's not.

I did some websearch but couldn't find a solution. Does anyone of you know how to fix it?