Fatal error: Uncaught Error: Class "Sabre\DAVACL\AbstractPrincipalCollection" not found in /home/tzuovhm/tzuovhm/apps/dav/lib/Avatars/RootCollection.php:12 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/apps/dav/lib/Avatars/RootCollection.php on line 12