Fatal error: Uncaught TypeError: Argument 1 passed to Lead::insertData() must be of the type string, null given, called in /var/www/html/index.php on line 21 and defined in /var/www/lead.php:13 Stack trace: #0 /var/www/html/index.php(21): Lead->insertData(NULL, NULL, NULL, Array) #1 {main} thrown in /var/www/lead.php on line 13