Fatal error: Uncaught PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'sender' cannot be null in /var/www/html/public/get/subscribe.php:39 Stack trace: #0 /var/www/html/public/get/subscribe.php(39): PDOStatement->execute() #1 {main} thrown in /var/www/html/public/get/subscribe.php on line 39