MediaUriElement cannot render

[bourne-3]

VideoControl= this.Template.FindName("MediaPlayer", this) as MediaUriElement;
var source = "url that can play video"
VideoControl.Source = new Uri(source);
VideoControl.Play();

And I got a exception: ”could not render any streams from the source Uri“
I don't have this problem on my development machine, but it happens on the client machine. how to solve

[Toprakete]

SAme here on my development maschine. Are there some needed dependencies?