I had a code that worked unlit few days ago: this is an xamarin.android activity 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<Button>(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<bool> 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();
    }
}

```

i did all the instruction in the [tutorial](https://learn.microsoft.com/en-us/azure/app-service-mobile/app-service-mobile-xamarin-android-get-started-users).
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"

i am working with 3.1 azure sdk version