But still very confusing to a user that wants to do some migration for some reason. It would be more intuitive if you could delete first and then get a message in contacts that you should first create an addressbook before contacts is usable.
Just to add to this solution - if you removed the contacts_birthday subscription as a user, then you need to re-generate the subscription calendar specifically for that user:
./occ dav:sync-birthday-calendar
Hi Micha-Btz,
where did you find the logs in DAVDroid? I am mostly interested in the following posted expression, as I would like to access my birthday calendar via ICS (read only), but could only find the direct link to the calendar, where you always need to log in: HTTP REQUEST: PUT /remote.php/caldav/calendars/MichaDO/contact_birthdays/431f1fde-fd75-4b8c-8ba9-0854a31dd49b.ics If-Match: “b24b014ac8d13a5c8a3b128eb95ae215”
So I am missing the access 431f1fde-fd75-4b8c-8ba9-0854a31dd49b for my birthday calendar