Hetzner online is a German data center operator and Web space provider. KonsoleH is their domain domain configuration backend which includes email support and also provides CalDAV/CardDAV.
DAVx⁵ settings
Base URL: https://webmail.your-server.de/rpc.php/
Username / Password: Use the same email-address/password combination of your email address.
Contact group method: Choose "groups are per-contact categories". Contact groups are mapped to labels in KonsoleH.
Known limitations
Horde Turba modifies uploaded contacts (vCards) and drops unknown fields, like certain telephone number/email address types, information about preferred numbers, etc.