GMX

Setup

Select the "GMX" option when setting up a new account.

CalDAV-Sync

• Username: your gmx mail address (example@gmx.net)
• Password: your password

CardDAV-Sync

• Server URL: https://carddav.gmx.net
• Use SSL: leave checked
• Username: your full gmx mail address (example@gmx.net)
• Password: your password

Issues

GMX doesn't support contact groups.