Why is youtube looping not working?

Question

YouTube

<iframe frameborder="0" height="100%" width="100%" 
    src="https://youtube.com/embed/jvSqlmh4iu0?autoplay=1&controls=0&look=1&showinfo=0&autohide=1">
  </iframe>

look=1 - this parameter does not work at all, what could be the reason?
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It doesn't work that way either

<iframe frameborder="0" height="100%" width="100%" 
    src="https://youtube.com/embed/jvSqlmh4iu0?autoplay=1&controls=0&look=1&showinfo=0&autohide=1&playlist=jvSqlmh4iu0">
  </iframe>

Values: 0 or 1. Default value: 0. If the value is 1, then the single player will play the video in a circle, in an endless loop. The playlist player (or custom player) plays the content of the playlist in a loop.
Note. This setting has limited support in the AS3 player and when embedding an IFrame to load an AS3 or HTML5 player. Currently, the loop parameter only works in the AS3 player when used in conjunction with the playlist parameter. To loop a single video, set the loop parameter to 1 and set the playlist parameter to the same video ID as in the Player API URL:
https://developers.google.com/youtube/player_param...

Answer 1

Probably because loop=1 should be correct