i had this error the other day when i was adding an auto play video to a page.

the error was:

Javascript

Uncaught (in promise) DOMException: play() failed because the user didn't interact with the document first. https://goo.gl/xX8pDD
video_play @ (index):507

i had this script to play the video if it was not playing

Javascript

    function video_play() {
        video = document.getElementById('my_video');
        var isPlaying = video.currentTime > 0 && !video.paused && !video.ended && video.readyState > 2;

        if (!isPlaying) {
          video.play();
        }
    }
    setTimeout(video_play, 1000);

Apparenly this is caused if your video has sound, so all you need to do is add the muted tag to the video element. 

So if you are getting this error just add muted="muted" to your video tag and it should fix the issue. 

HTML

    <video id="my_video" loop autoplay muted="muted">
        <source src="video.mp4" type="video/mp4">
    </video>