I think they updated the html5 video and deprecated some codecs. It worked for me after removing the codecs.
In the below example:
<video>_x000D_
<source src="sample-clip.mp4" type="video/mp4; codecs='avc1.42E01E, mp4a.40.2'">_x000D_
<source src="sample-clip.webm" type="video/webm; codecs='vp8, vorbis'"> _x000D_
</video>_x000D_
_x000D_
must be changed to_x000D_
_x000D_
<video>_x000D_
<source src="sample-clip.mp4" type="video/mp4">_x000D_
<source src="sample-clip.webm" type="video/webm">_x000D_
</video>
_x000D_