Hey @YouTube! For some reason i cannot go in fullscreen mode while viewing a video. Weirdly enough when i logout and login via a different account i can go fullscreen, but then again when i logged back into my own account fullscreen doesn't work. I'm using Firefox Quantum on PC.
@YouTube @TeamYouTube I somehow managed to fix it by reverting to the old layout and changing back to the new. And now I can go fullscreen without any problems.