Facebook\Exceptions\FacebookSDKException: Required "app_secret" key not supplied in config and could not find fallback environment variable "FACEBOOK_APP_SECRET" in /var/www/vhosts/shulcloud.com/vendor/facebook/php-sdk-v4/src/Facebook/Facebook.php:142 Stack trace: #0 /var/www/vhosts/shulcloud.com/htdocs/login.php(406): Facebook\Facebook->__construct(Array) #1 {main}