
GMX is a German Web portal which provides an email service with address books and calendars.
DAVx⁵ settings
Two separate DAVx⁵ accounts are required (one for CalDAV, another for CardDAV) because there are no SRV records.
For CalDAV:
- either use "Login with email address", or
- base URL:
https://caldav.gmx.net
For CardDAV, use this base URL: https://carddav.gmx.net
User name: your GMX email address
Password: your GMX password
Contact group method: VCard contact groups are not supported. Choose the method used by your other clients or "per-contact categories" to minimize potential problems.