title: TweetSharp GetRequestToken The request token for this page is invalid
body: <p>I am using TweetSharp Api and I have some problems concerning the service.GetRequestToken().</p>
  
  <p>here's my code:-</p>
  
  <pre><code>TwitterService service = new TwitterService("######", "######");
  OAuthRequestToken requestToken = service.GetRequestToken();
   Uri uri = service.GetAuthorizationUri(requestToken);
          Process.Start(uri.ToString());
  </code></pre>
  
  <p>The problem is that when I'm redirected to the Twitter authorization window this message is come :-</p>
  
  <pre><code>Whoa there!
  The request token for this page is invalid. It may have already been used, or expired because it is too old. Please go back to the site or application that sent you here and try again; it was probably just a mistake.
  </code></pre>
  
  <p>the uri is like :</p>
  
  <pre><code>https://api.twitter.com/oauth/authorize?oauth_token=?
  </code></pre>
  
  <p>any help ?</p>
  
  <p>thanks in advance.</p>