To allow your custom app to connect to the internet, add the following in your AndroidManifest.xml file right before (outside) the application tag.
<uses-permission android:name="android.permission.INTERNET" />
In general this issue is caused when a referenced resource cannot be found.
<Application x:Class="AppName.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" StartupUri="MainWindow.xaml"> <Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="/PresentationFramework.Aero;component/themes/Aero.NormalColor.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Application.Resources> </Application>
In my specific circumstance, as the xaml above details, this issue was caused by a reference to PresentationFramework.Aero DLL that was not contained in the output bin folder of the compiled project. Under references, setting Copy Local to true did the trick for me.