PHP Error 

Error: Undefined index: key
File: /home/www/social.tio.ch/public/vendor/hybridauth/hybridauth/hybridauth/Hybrid/Provider_Model_OAuth1.php
Line: 75

Call history 

  Function initialize()
  Function initialize()
  Function __construct(Twitter)
  Function factory(twitter)
  Function setup(twitter)
  Function authenticate(twitter)
  Function authenticate(twitter)