Xamarin.Forms.WebView not loading URL ?

public class WebPage : ContentPage
{
    public WebPage ()
    {
        var browser = new WebView();
        browser.Source = "http://Xamarin.com";
        Content = browser;
    }
}

I tried the above coding, working fine. But when I change the URL, let say browser.Source = "http://google.com"... it is not working. The WebView is not loading, it is only load xamarin.com ... why?

Please help if anybody facing the same issue before and found the solution ... thanks in advance.