Fatal error: Uncaught Facebook\Exceptions\FacebookSDKException: Sessions are not active. Please make sure session_start() is at the top of your script. in /var/www/html/dynamic/facebook/fbsdk4-5.1.2/src/Facebook/PersistentData/FacebookSessionPersistentDataHandler.php:50 Stack trace: #0 /var/www/html/dynamic/facebook/fbsdk4-5.1.2/src/Facebook/PersistentData/PersistentDataFactory.php(57): Facebook\PersistentData\FacebookSessionPersistentDataHandler->__construct() #1 /var/www/html/dynamic/facebook/fbsdk4-5.1.2/src/Facebook/Facebook.php(155): Facebook\PersistentData\PersistentDataFactory::createPersistentDataHandler('session') #2 /var/www/html/dynamic/facebook/login.php(12): Facebook\Facebook->__construct(Array) #3 /var/www/html/inc/pages/login.php(87): require_once('/var/www/html/d...') #4 /var/www/html/inc/pages/login.php(59): ShowFormLogin() #5 /var/www/html/index.php(0): unknown() #6 {main} thrown in /var/www/html/dynamic/facebook/fbsdk4-5.1.2/src/Facebook/PersistentData/FacebookSessionPersistentDataHandler.php on line 50