Fatal error: Uncaught Error: Class "Sabre\DAV\Collection" not found in D:\xampp\htdocs\pimcore\my-project\vendor\sabre\dav\lib\CardDAV\AddressBook.php:19 Stack trace: #0 {main} thrown in D:\xampp\htdocs\pimcore\my-project\vendor\sabre\dav\lib\CardDAV\AddressBook.php on line 19