WebView not showing html web page in simulator

I have the following xaml

`<?xml version="1.0" encoding="utf-8" ?>

<ContentPage.Content>

  <!--<Label x:Name="message" Text="here" VerticalOptions="Center" HorizontalOptions="Center" />-->

  <WebView x:Name="webView1"
           HeightRequest="100"
           WidthRequest="100"
           HorizontalOptions="FillAndExpand"
           VerticalOptions="FillAndExpand"              
           />


  <WebView Source="http://www.xamarin.com/"
    HeightRequest="1000"
    WidthRequest="1000" />

  <!--<WebView x:Name="webView"></WebView>-->

  <Button Text="Next" Clicked="Nav_OnClick" BackgroundColor="Gray"  TextColor="White"></Button>

</StackLayout>

</ContentPage.Content>
`

In the code behind i am setting the source of webView1 via the following...neither webviews show the html content from the internet.

var URLReportsListWebView = new UrlWebViewSource {
                Url = "http://www.yahoo.com/"
            };
            webView1.BackgroundColor = Xamarin.Forms.Color.Transparent;
            webView1.Source = URLReportsListWebView;

Is there any particular reason for this issue? (all i see in the simulator is a blank screen)