Fatal error: Uncaught Error: Interface "Sabre\DAV\ICollection" not found in /var/www/illumine/vendor/sabre/dav/lib/DAVACL/IPrincipalCollection.php:17 Stack trace: #0 {main} thrown in /var/www/illumine/vendor/sabre/dav/lib/DAVACL/IPrincipalCollection.php on line 17