Property “Background” does not support values of type “Frame” error in xamarin forms

Checking the documentation of VisualElement.Background Property shows, the Background property is of type Brush. Applying a Frame will not work. So the solution is to apply the brush without the frame:

<StackLayout>
    <StackLayout.Background>
        <LinearGradientBrush EndPoint="0,1">
            <GradientStop Color="#48b6a6" Offset="0.1" ></GradientStop>/>
             <GradientStop Color="#2b78d4" Offset="1.0" ></GradientStop>/>
         </LinearGradientBrush>
    </StackLayout.Background>
</StackLayout>