Fatal error: Uncaught Error: Class "Sabre\Xml\Service" not found in /var/www/apache/dev/cal/web/vendor/sabre/dav/lib/DAV/Xml/Service.php:12 Stack trace: #0 {main} thrown in /var/www/apache/dev/cal/web/vendor/sabre/dav/lib/DAV/Xml/Service.php on line 12