4 ms·
Not sure about this particular case, but this will happen if you're using the HTML5 version of Youtube and the video is inside an iframe that doesn't have the a
by burkaman 12y ago
Not sure about this particular case, but this will happen if you're using the HTML5 version of Youtube and the video is inside an iframe that doesn't have the allowfullscreen attribute.
However in this case, the fullscreen button appeared for me after I clicked play.