Windows Phone 8 Bing Translator API

Question

我在Windows Azure Marketplace中使用Bing Translator API和Access Token，我获得了在应用中定义的语言代码

它有时会起作用，有时它不起作用，它会抛出这样的错误：

类型＆＃39; System.UnauthorizedAccessException＆＃39;的例外情况发生在System.Windows.ni.dll中但未在用户代码中处理

我更改了访问令牌两次（clientId，clientSecret），它首先工作，然后再次开始显示此异常，我已经到处搜索，我无法在这里找到解决方案＆＃39;使用的代码：

private void TranslationReady(IAsyncResult ar)
{
   try
        {

            HttpWebRequest request = (HttpWebRequest)ar.AsyncState;

            HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(ar);

            System.IO.Stream streamResponse = response.GetResponseStream();
            System.IO.StreamReader streamRead = new System.IO.StreamReader(streamResponse);
            string responseString = streamRead.ReadToEnd();

            System.Xml.Linq.XDocument xTranslation =
              System.Xml.Linq.XDocument.Parse(responseString);
            string strTest = xTranslation.Root.FirstNode.ToString();

            Deployment.Current.Dispatcher.BeginInvoke(() => TextBlock2.Text = strTest);
        }
        catch (WebException e)
        {

            var status = e.Status;
            var response = e.Response;
            var msg = e.Message;
            MessageBox.Show(status.ToString() + response.ToString() + msg.ToString());
        }

        }