Fatal error: Uncaught Facebook\FacebookSDKException: You must provide or set a default application id. in /var/www/Codesvilla/vendor/facebook/php-sdk-v4/src/Facebook/FacebookSession.php:320 Stack trace: #0 /var/www/Codesvilla/vendor/facebook/php-sdk-v4/src/Facebook/FacebookRedirectLoginHelper.php(75): Facebook\FacebookSession::_getTargetAppId(NULL) #1 /var/www/Codesvilla/includes/Library/Coupons/User/Auth/Facebook.php(20): Facebook\FacebookRedirectLoginHelper->__construct('https://codesvi...') #2 /var/www/Codesvilla/includes/Controllers/Home/Login.php(36): Coupons\User\Auth\Facebook->Auth(NULL) #3 [internal function]: Controllers\Home\Login->Facebook() #4 /var/www/Codesvilla/includes/Library/Origin/Router/Router.php(96): call_user_func_array(Array, Array) #5 /var/www/Codesvilla/includes/Library/Origin/Router/Router.php(35): Origin\Router\Router->PathFinder('Home/Login/Face...', 'login/oauth/fac...') #6 /var/www/Codesvilla/index.php(3): Origin\Router\Router->Route() #7 {main} thrown in /var/www/Codesvilla/vendor/facebook/php-sdk-v4/src/Facebook/FacebookSession.php on line 320