Video autoplay doesn't work on all iphone

问题

On the top of this homepage, I have a video with muted, autoplay and playsinline attributes.

The video is autoplaying on desktop & mobile I've tested (Chrome, Safari, Firefox). Surprisingly, the video is not playing for lots of iPhone users, they have a PLAY button showing, requiring interaction then.

Here is my code :

<video id="vid" width="100%" height="auto" preload="auto" autoplay muted playsinline>
  <source src="http://www.nevada-club.com/wp-content/uploads/2018/06/Nevada_Club.mp4" type="video/mp4" />
  <source src="http://www.nevada-club.com/wp-content/uploads/2018/06/Nevada_Club.webm" type="video/webm" />
  <source src="http://www.nevada-club.com/wp-content/uploads/2018/06/Nevada_Club.ogg" type="video/ogg" />
</video>

<script>
     var herovide = document.getElementById('vid');
       herovide.autoplay=true;
       herovide.load();  
</script>

Does someone knows why some people have this issue and how to fix it ? Somebody who has this issue was on iOS 11.4.

Thanks