Fatal error: Uncaught Error: Class "OCA\DAV\CardDAV\Activity\Provider\Base" not found in /var/www/html/nextcloud/apps/dav/lib/CardDAV/Activity/Provider/Addressbook.php:21 Stack trace: #0 {main} thrown in /var/www/html/nextcloud/apps/dav/lib/CardDAV/Activity/Provider/Addressbook.php on line 21