Any Ninja for a YouTube player issue?

Hello everyone!

I’m setting up a new theme that has the functionality to show a YouTube or Vimeo video on the product page.

The URL is correct and works if pasted directly on the browser, but in the theme I got this message.

Tested in Chrome, Opera and Firefox.

I’ve also tested the link shown directly on the video if you press the share button but is the same.

I’ve been told that could be something regarding an auto play functionality but I don’t even know how or where this might be.

Some kind soul has a solution?

Thank you in advance!