Youtube API - Failed to execute 'postMessage' on 'DOMWindow'

Question

I\'m trying to start a youtube video when a modal is opened and not progress to the next page until it is completed.

My script below works in Chrome but produces thi

Answer 1

In my case (similar to the selected answer here Youtube API error - Failed to execute 'postMessage' on 'DOMWindow':) It came down the to the fact that the video was not visible on the page at the time Player was instantiated.