MAC and GW-Addressbook


when visit my GW caldav server with a web-browser (and login) I found
under https://<caldavsrv>/principials/users a list of all users followed
by uid of the logged in user. I choose the link behind
{DAV:}current-user-principal and get the addressbook and calenders. This
looks good.

But what is the way to get these information into the MAC-Contacts?

I test this with MAC (10.13.6) and its default apps, Thunderbird 60
(incl. a CardDAV-Extension) and KDE-Addressbook. None of them can read
the answers from the GW-caldav-Server.

Any Hints?