CardDAV sync problem

I'm trying to sync contacts with CardDAV account from my own server.

In console I've got errors:

AddressBookSourceSync	No groups for collection path: /addressbooks/afe4c45d-d647-41ab-97bf-42c29429b9f4/d950c448-95a3-4c42-aed3-660dd443f0c9/
AddressBookSourceSync	-_handleAddsOrModifies:https://slava@localhost/addressbooks/afe4c45d-d647-41ab-97bf-42c29429b9f4/d950c448-95a3-4c42-aed3-660dd443f0c9/ Error Domain=CoreDAVErrorDomain Code=3 "(null)"

Please, help me understand what does AddressBook want and what's wrong?

As I understand it cannot sync my addressbook, but why?