Fatal error: Uncaught Error: Class "Sabre\DAV\Collection" not found in C:\Apache24\htdocs\dle\engine\classes\composer\vendor\sabre\dav\lib\CalDAV\Schedule\Inbox.php:20 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\dle\engine\classes\composer\vendor\sabre\dav\lib\CalDAV\Schedule\Inbox.php on line 20