title: Xamarin Forms Google Authenticateion, Error: disallowed_useragent
body: <p>Currently I am developing Xamarin Forms application and I added Google Authentication.
  Here is my code from PCL:</p>
  
  <pre>
  var authenticator = new OAuth2Authenticator(
      clientId,
      null,
      Constants.Scope,
      new Uri(Constants.AuthorizeUrl),
      new Uri(redirectUri),
      new Uri(Constants.AccessTokenUrl),
  
      null,
      true);
  
  authenticator.Completed += this.OnAuthCompleted;
  authenticator.Error += this.OnAuthError;
  
  AuthenticationState.Authenticator = authenticator;
  
  var presenter = new Xamarin.Auth.Presenters.OAuthLoginPresenter();
  presenter.Login(authenticator);</pre>
  
  <p>I am using latest version of <code>Xamarin.Auth</code>, which is <code>1.5.0.3</code>
  This is what I receive: <a href="http://prntscr.com/g9y722" rel="nofollow noreferrer">Screenshot</a></p>
  
  <p>I went through many articles and code examples, but looks like maybe google updated their authentication once again. <a href="https://forums.xamarin.com/discussion/86415/google-auth-error-disallowed-useragent" rel="nofollow noreferrer">Link 1</a>, <a href="https://github.com/xamarin/Xamarin.Auth/issues/137" rel="nofollow noreferrer">Link 2</a>, <a href="https://stackoverflow.com/questions/42884941/xamarin-auth-getting-disallowed-useragent-error-xamarin-forms">Link 3</a>, <a href="https://stackoverflow.com/questions/43517508/xamarin-forms-app-throwing-disallowed-useragent-error-with-google-authentication">Link 4</a>. Event on official page for Xamarin.Forms example is invalid and not working <a href="https://developer.xamarin.com/guides/xamarin-forms/cloud-services/authentication/oauth/" rel="nofollow noreferrer">Link 5</a>.</p>
  
  <p>I checked several code examples, but again no success, <a href="https://github.com/moljac/Xamarin.Auth.Samples.NugetReferences/tree/master/Xamarin.Forms/Evolve16Labs" rel="nofollow noreferrer">Sample 1</a> and multiple samples <a href="https://github.com/xamarin/Xamarin.Auth/tree/master/samples/Xamarin.Forms" rel="nofollow noreferrer">here</a>. I download source and tried to use it, expecting that it's working, but they're failing as well.</p>
  
  <p>Do you have solution for this issue or any article, which is up to date and you know it's working. As well code sample would be brilliant. </p>
  
  <p>Thanks in advance!</p>