title: Facebook OAuthException: The access token could not be decrypted
body: <p>I have a running application that does scheduled wall posts to one of their friends on behalf of the user.</p>
  
  <p>The application was running fine for quite some time but recently quiet a few of the users have reported the messages not being posted.</p>
  
  <p>The logs shows</p>
  
  <pre><code>OAuthException: The access token could not be decrypted. 
  </code></pre>
  
  <p>Even if the user revisits the application and resets their Access token the exception persists.</p>
  
  <p>What may be the root of the error and ways to work around it?</p>