Fatal error: Uncaught Error: Class "Sabre\DAV\ServerPlugin" not found in /usr/home/jiexusheng/domains/linuxdo.isgre.at/public_html/vendor/sabre/dav/lib/CalDAV/Subscriptions/Plugin.php:22
Stack trace:
#0 {main}
  thrown in /usr/home/jiexusheng/domains/linuxdo.isgre.at/public_html/vendor/sabre/dav/lib/CalDAV/Subscriptions/Plugin.php on line 22