Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /www/classes/database.class.php:23 Stack trace: #0 /www/classes/database.class.php(17): Database->open_connection() #1 /www/classes/database.class.php(93): Database->__construct() #2 /www/includes/initialize.inc.php(5): require_once('/www/classes/da...') #3 /www/mollie/prepare-payment.php(10): require_once('/www/includes/i...') #4 {main} thrown in /www/classes/database.class.php on line 23