title: authentication with Xamarin. Android and Microsoft.Azure.Mobile.Client Microsoft provider error
body: <p>I had a code that worked unlit few days ago: this is an xamarin.android activity code</p>
  
  <pre><code>[Activity(Label = "AuthSample", MainLauncher = true, Icon = "@drawable/icon")]
  public class MainActivity : Activity
  {
      Button login;
      //Mobile Service Client reference
      private MobileServiceClient client;
  
      protected override void OnCreate(Bundle bundle)
      {
          base.OnCreate(bundle);
  
          // Create the Mobile Service Client instance, using the provided
          // Mobile Service URL and key
          client = new MobileServiceClient("https://XXXXXXX.azurewebsites.net");
  
          // Set our view from the "main" layout resource
          SetContentView (Resource.Layout.Main);
          login = FindViewById&lt;Button&gt;(Resource.Id.buttonLoginUser);
          login.Click += onLoginClick;
  
      }
  
      private async void onLoginClick(object sender, EventArgs e)
      {
          // Load data only after authentication succeeds.
          if (await Authenticate())
          {
  
          }
      }
  
      // Define a authenticated user.
      private MobileServiceUser user;
      private async Task&lt;bool&gt; Authenticate()
      {
          var success = false;
          try
          {
              // Sign in with Microsoft login using a server-managed flow.
              user = await client.LoginAsync(this,
                  MobileServiceAuthenticationProvider.MicrosoftAccount);
              CreateAndShowDialog(string.Format("you are now logged in - {0}",
                  user.UserId), "Logged in!");
  
              success = true;
          }
          catch (Exception ex)
          {
              CreateAndShowDialog(ex, "Authentication failed");
          }
          return success;
      }
  
  
      private void CreateAndShowDialog(Exception exception, String title)
      {
          CreateAndShowDialog(exception.Message, title);
      }
  
      private void CreateAndShowDialog(string message, string title)
      {
          AlertDialog.Builder builder = new AlertDialog.Builder(this);
  
          builder.SetMessage(message);
          builder.SetTitle(title);
          builder.Create().Show();
      }
  }
  </code></pre>
  
  <p>i did all the instruction in the <a href="https://docs.microsoft.com/en-us/azure/app-service-mobile/app-service-mobile-xamarin-android-get-started-users" rel="nofollow noreferrer">tutorial</a>.
  the LoginAsync redirect me to the Microsoft login page, i am able to authenticate and after a successful authentication i get this error : "the page cannot be displayed because an internal server error has occured"</p>
  
  <p>i am working with 3.1 azure sdk version</p>