Glitchy Orientation Video

[Winston Smith]

Clicking "Orientation Video" throws the following exception :

InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable

Video cannot be viewed unless guessing and using contextual menu : right click on the middle of the totally black modal, then "Play". GIF File : https://theswanstation.tk/assets/img/film-projector.gif won't show either.

Currently using Firefox 43.0.4. It worked .... only one time. Haven't bothered to check why.