Comment 73 for bug 1589008

BT device is in the wrong mode / on the wrong profile.

Solution is here: https://askubuntu.com/questions/889737/video-not-playing-in-web-browser-with-bluetooth-headphones-connected-how-can-i

wget https://gist.github.com/pylover/d68be364adac5f946887b85e6ed6e7ae/archive/d698974910bbb7d016ec0ad08c1bf41b4b524364.zip

unzip d698974910bbb7d016ec0ad08c1bf41b4b524364.zip

in there is a a2dp.py

chmod +x a2dp.py

Run the file (modify python3.5 to python3 if needed in the first line) when you have the device connected.

Choose it from the list.

It changes the profile, now everything works, the video is also running. What the reason is, I cant tell, but I can tell you that this solves it