title: Can't get response code
body: <p>I want to get user AccessToken. </p>
  
  <p>When the user clicks on Register/Login button : </p>
  
  <pre><code>            $.ajax({
              url: 'Register',
              type: 'GET',
              data: { m:true },
              contentType: 'application/json; charset=utf-8',
              success: function (response) {
                  if (response.success) {
                  } else {
                  }
              },
              error: function () {
              }
              });
  </code></pre>
  
  <p>My register method : </p>
  
  <pre><code>            Uri uri = new Uri(FacebookHelpers.GetFacebookLoginURL());
              var res = await FacebookHelpers.FacebookRequest&lt;object&gt;(uri).ConfigureAwait(false);
  </code></pre>
  
  <p>In res, i want to get result from FacebookRequest to get code, than exchange that code for access token. </p>
  
  <p>My GetFacebookLoginUrl function : </p>
  
  <pre><code>            var redirectUri = "https://www.facebook.com/connect/login_success.html";
              var uri = GetUri("https://www.facebook.com/dialog/oauth",
                  Tuple.Create("client_id", FacebookAppId),
                  Tuple.Create("redirect_uri", redirectUri),
                  Tuple.Create("response_type", "code"),
                  Tuple.Create("scope", "public_profile,email"),
                  Tuple.Create("state", Convert.ToString(new Random().Next(9999)))
                  );
  </code></pre>
  
  <p>In my FacebookRequest function : </p>
  
  <pre><code>        public static async Task&lt;T&gt; FacebookRequest&lt;T&gt;(Uri uri)
          {
              string json;
              using (HttpClient client = new HttpClient())
              {
                  json = await client.GetStringAsync(uri).ConfigureAwait(false);
              }
  
              try
              {
                  var result = JsonConvert.DeserializeObject&lt;T&gt;(json);
                  return result;
              }
              catch (JsonException ex)
              {
                  throw new ArgumentException("Unable to deserialize the Facebook response.", ex);
              }
          }
  </code></pre>
  
  <p>The issue appears when FacebookRequest function tries to get code from provided URL. </p>
  
  <blockquote>
    <p>Unexpected character encountered while parsing value: &lt;. Path '', line
    0, position 0.</p>
  </blockquote>
  
  <p>Json response contains same page from where method has been called.
  FacebookRequest does not returns code, it returns success instead. </p>
  
  <p>Any idea ?</p>
  
  <p>The goal : I want to get user from my database and link its account with my bot. Or if user does not exist, first register and than link with the bot.</p>