Fatal error: Uncaught Error: Class 'HTMLPurifier_Strategy' not found in /home/app/htdocs/ninja/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/ValidateAttributes.php:7 Stack trace: #0 {main} thrown in /home/app/htdocs/ninja/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Strategy/ValidateAttributes.php on line 7