title: 400 Client Error: Bad Request using python-social-auth for Facebook auth in Django
body: <p>Lately some strange errors have happened in a project I'm working on. It was working perfectly fine when one day (without any changes on our side that I know of) Facebook authentication with python-social-auth for django stopped working. The error given was "400 Client Error: Bad Request" and seemingly occurred in the /complete/facebook callback.</p>
  
  <p>I have tried switching to older code, creating a new Facebook app from scratch and switching the settings of the existing one, all to no avail.</p>
  
  <p>Does anybody have any idea on how to fix this? Help would be greatly appreaciated.</p>
  
  <p>Thanks in advance.</p>