Fatal error: Uncaught Facebook\Exceptions\FacebookSDKException: Required "app_id" key not supplied in config and could not find fallback environment variable "FACEBOOK_APP_ID" in /htdocs/core/library/facebook/Facebook.php:139 Stack trace: #0 /htdocs/core/controllers/facebook.php(38): Facebook\Facebook->__construct(Array) #1 /htdocs/core/app.php(148): require('/htdocs/core/co...') #2 /htdocs/index.php(25): require('/htdocs/core/ap...') #3 {main} thrown in /htdocs/core/library/facebook/Facebook.php on line 139