moved to muse forum
Actually the video widget I was originally using actually does work, just not on Safari.
If anyone didn't know, Safari is not compatible with Youtube 360.
It doesn't work.
I copy the <iframe - html code of 360-videos from youtube to Muse --> "Insert HTML".
The video appears, you can start it...but its flat and the 360-moving/scrolling-function isn't working in the Muse-preview-mode.
Any ideas, why it isn't working?
(no, I don't use safari).