YouTube autoplay not working in Chrome

(One) of the possible solution taken from the comments discussion would be muting the video if sound isn't that important in your case (if it is, I'll leave the answer as it could help other people).

It's apparently the only way to have autoplay always enabled. From the article :

"Muted autoplay is always allowed."

Source : Google changelog

Simply add in your playerVars:

mute : 1

Source for the muted video

You should put the allow="autoplay" on the embedding iframe element

<!-- Autoplay is allowed. --><iframe src="https://cross-origin.com/myvideo.html" allow="autoplay"><!-- Autoplay and Fullscreen are allowed. --><iframe src="https://cross-origin.com/myvideo.html" allow="autoplay; fullscreen">

Chrome's autoplay policies :

• Top frames can delegate autoplay permission to their iframes to allow autoplay with sound.
• Muted autoplay is always allowed.
• Autoplay with sound is allowed if:
  • User has interacted with the domain (click, tap, etc.).
  • On desktop, the user's Media Engagement Index threshold has been crossed, meaning the user has previously play video with sound.
  • On mobile, the user has added the site to their home screen.

Google chrome removed the autoplay functionality. See below:

https://developers.google.com/web/updates/2017/09/autoplay-policy-changes