mobile iframes error

I have the lightbox as in iframe format linked to a mp4 video. When clicking the link on an iphone 5 or 6, the lightbox opens up but the video does not autoplay. Furthermore, the play button is offset to the right, and half of it is gone.

example: http://www.medicalalertsystemsratings.com/
on iphone, click on blue video button in top of site
it does not autoplay like it does on the desktop and ipad, but not iphone. Secondly, the play button is offset to the right.

https://wordpress.org/plugins/wp-video-lightbox/