title: Error validating verification code when requesting Facebook Token Server Side
body: <p>I am using Facebook API for logging in users for my site. I am developing it in ASP.NET 4.5/C#.</p>
  
  <p>I use server side to get the access token. Here's the part of the good that I get the exception from:</p>
  
  <pre><code>dynamic response = fb.Get("oauth/access_token",
      new  { 
       client_id = facebookAppId,
       redirect_uri = System.Configuration.ConfigurationManager.AppSettings["WebsiteUrl"] +
      "oauth-redirect/facebook/",
      client_secret = facebookSecret,
      code = facebookCode 
      });
  </code></pre>
  
  <p>When I try to login, I get the following exception:</p>
  
  <blockquote>
    <p>(OAuthException - #100) Error validating verification code. Please
    make sure your redirect_uri is identical to the one you used in the
    OAuth dialog request</p>
  </blockquote>
  
  <p>I viewed other related question about this subject, and I checked the end slash and tried with encoded URL, but nothing works.</p>
  
  <p>The URL I pass for the <strong>redirect_uri</strong> parameter is (I run and test my site locally):</p>
  
  <pre><code>http://localhost:2194/oauth-redirect/facebook/
  </code></pre>
  
  <p>It worked before, but for some reason it doesn't work now. I am using the <a href="https://github.com/facebook-csharp-sdk/facebook-csharp-sdk" rel="nofollow">Facebook SDK for .NET by Outercurve Foundation</a> version 7.0.6, which I installed via Nuget. Thanks.</p>
  
  <p>The URL </p>