Fatal error: Uncaught Error: Class 'HTMLPurifier_AttrTransform' not found in /var/www/app/appregwebservice/vendor/ezyang/htmlpurifier/library/HTMLPurifier/AttrTransform/SafeEmbed.php:3 Stack trace: #0 {main} thrown in /var/www/app/appregwebservice/vendor/ezyang/htmlpurifier/library/HTMLPurifier/AttrTransform/SafeEmbed.php on line 3