Fatal error: Uncaught Error: Class "HTMLPurifier_Lexer" not found in /srv/www/htdocs/moodle/lib/htmlpurifier/HTMLPurifier/Lexer/DOMLex.php:27 Stack trace: #0 {main} thrown in /srv/www/htdocs/moodle/lib/htmlpurifier/HTMLPurifier/Lexer/DOMLex.php on line 27