title: Sending Facebook notifications to user with app_secret
body: <p><strong>I have been trying to send notifications to my users via Graph API.</strong></p>
  
  <p>But <strong>I was facing with "An unknown error has occurred." error. There wasn't any further information.</strong> I was have SSL, Canvas Page and also Website integration with my App but it didn't worked.</p>
  
  <p>Also Google couldn't help me.</p>