Xamarin mediaPicker.TakePhotoAsync crashes app

[postlink] https://the-best-way-of-life-is-islam.blogspot.com/2015/07/xamarin-mediapickertakephotoasync.html [/postlink]

I have an Xamarin.Forms app that uses XLabs, it was working fine, but suddenly it started to crash my app, if I take photo or press back button from photo screen, I was googling around for 4 hours and still have no idea why it happening, any ideas or thoughts, please help!

here is my lines of code:

    private async Task TakePicture()
    {
        mediaPicker = Resolver.Resolve<IDevice>().MediaPicker;

        try
        {
            var mediaFile = await mediaPicker.TakePhotoAsync(new CameraMediaStorageOptions
            {
                DefaultCamera = CameraDevice.Front,
                MaxPixelDimension = 1,
                PercentQuality = 2,
            });

            var image = GetResizedImage(mediaFile.Source, 990, 560);
            OnImageUpdate(this, image);
        }
        catch (Exception ex)
        {
            this.status = ex.Message;
        }
    }

my permission are alright:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />