title: Twitter API - Reasons for "invalid or expired token"
body: <p>What are the possible reasons that can cause token to become expired (besides having the user un-authorising the app)?</p>
  
  <p>My problem is that I have an app with several thousands of users, all API communication works perfectly but for some users I am getting the <code>invalid or expired token</code> error, my initial though was that they are users who canceled the authentication to the app but I've contacted some of them and they haven't revoked the access.</p>
  
  <p>Any ideas what other issues can cause that error?</p>