Fatal error: Uncaught Error: Class 'HTMLPurifier_ChildDef' not found in /var/www/app/appregwebservice/vendor/ezyang/htmlpurifier/library/HTMLPurifier/ChildDef/Required.php:6 Stack trace: #0 {main} thrown in /var/www/app/appregwebservice/vendor/ezyang/htmlpurifier/library/HTMLPurifier/ChildDef/Required.php on line 6