MediaPlayer stops playing altought it should loop

I have .NET 4.7, on Windows 10.

I have following code:

``` MediaTimeline timeline2 =
new MediaTimeline(new Uri(Configuration.Instance.UvodLeva, UriKind.Relative));
MediaClock clock2 = timeline2.CreateClock();
MediaPlayer player2 = new MediaPlayer();
player2.Clock = clock2;
VideoDrawing drawing2 = new VideoDrawing();
drawing2.Rect = new Rect(0, 0, 768, 432);
drawing2.Player = player2;
DrawingBrush brush2 = new DrawingBrush(drawing2);
timeline2.RepeatBehavior = RepeatBehavior.Forever;
GridLava.Background = brush2;
```

Video should repeat forever but it doesn't even finish first loop and stops.