How to fix: HTML5 video not working in IE9
Microsoft does not support IE9 anymore, and neither do we.
While IE9 does support HTML5 <video> tags, it fails to work until you force HTML5 mode.
Here are two ways to do that.
Option 1: Doctype
Make sure your HTML document uses HTML5. It should start like this:
<!DOCTYPE html>
Option 2: Magic meta tag
If you can not set a doctype, you use the X-UA-Compatible meta tag in your HTML <head>.
<meta http-equiv="X-UA-Compatible" content="IE=Edge"/>