azure mobile services authentication
I think you have not configured the account properly. Please provide the right Mobile service URL in the App registration page in live dashboard. If the URL is not right it is more likely to get such exceptions !
Old question but this helped me.
Quoting answer from MSDN Forums
I forgot to mention, that our tutorials are not yet updated for window phone 8.1, so you will also need to add the following code as well into your app.xaml.cs (this snippet is for a univeral app, phone 8.1 would be the same just without needing it to be conditional)
protected override void OnActivated (IActivatedEventArgs args){ base.OnActivated (args);#if WINDOWS_PHONE_APP if (args.Kind == ActivationKind.WebAuthenticationBrokerContinuation) App.<mobileservice>.LoginComplete (args as WebAuthenticationBrokerContinuationEventArgs);#endif}