Media source does not anything

I'm trying to implement a Media Player Element in an UWP app but I can't seem to get the Source working. When I visit this page, it doesn't show the media player and I can't play it.

Code Behind

public sealed partial class MoviesOverview : Page
{
        public MoviesOverview()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            vm.Movie = SerializationService.Json.Deserialize<Movie>(e.Parameter.ToString());
            SetSource();
        }

        private void SetSource()
        {
            mediaPlayer.Source = MediaSource.CreateFromUri(new Uri($"ms - appx:///Assets/Movies/{vm.Movie.Title}.mp4"));
        }
}

Using the Media Player Element

<MediaPlayerElement x:Name="mediaPlayer" Height="720" Width="1280" HorizontalAlignment="Center" VerticalAlignment="Center" />

Media source does not anything

You could check this line $"ms - appx:///Assets/Movies/{vm.Movie.Title}.mp4". Please don't add blank space in ms-appx:///. Then print above uri and make sure the media file exist in Assets/Movies folder. MediaPlayerElement could not autoplay by default. please set AutoPlay property as true like the following.

<MediaPlayerElement
    x:Name="mediaPlayer"
    Width="1280"
    Height="720"
    HorizontalAlignment="Center"
    VerticalAlignment="Center"
    AutoPlay="True"
    />

Code Behind

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    base.OnNavigatedTo(e);
    SetSource();

}
private void SetSource()
{
    mediaPlayer.Source = MediaSource.CreateFromUri(new Uri($"ms-appx:///Assets/{"test"}.mp4"));
}