title: OAuthException error in app center mobile authentication
body: <p>I'm trying to do authentication from app center for mobile devices but I get this error when I try to exchange code parameter for access token:</p>
  
  <pre><code>{
      "error": {
          "message": "Error validating verification code. Please make sure your redirect_uri is identical to the one you used in the OAuth dialog request",
          "type": "OAuthException",
          "code": 100
      }
  }
  </code></pre>
  
  <p>Auth token parameter is in Query String format because my app uses server-side authentication.</p>
  
  <p>The url I'm calling is <a href="https://graph.facebook.com/oauth/access_token" rel="nofollow">https://graph.facebook.com/oauth/access_token</a> and the redirect_uri parameter I'm sending to is like the following one:</p>
  
  <blockquote>
    <p><code>http://www.example.com?ref=app_directory&amp;code=codefromfb&amp;fb_source=appcenter_mobile&amp;fb_appcenter=1</code></p>
  </blockquote>
  
  <p>www.example.com is the value I've set in mobile site url field in app settings.</p>
  
  <p>Authentication from app center for web it's ok.</p>
  
  <p>I don't understand what it's wrong in redirect uri form mobile devices...</p>
  
  <p>Could you help me?</p>