Switch to the
Accounts tab and click the "+" button on the
lower left.
Select the
CalDAV account type.
Enter your GMX email address and
the application-specific password you created in step 1.
In the
Server address field, enter the path
https://caldav.gmx.com/.
Click
Create.
Your
GMX
Organizer is synchronized with the Mac OS
calendar.
Info:
If you retrieve your emails via POP3/IMAP, you will then need a separate
application-specific password. Use this instead of your usual password in the email
programme or the email app provided by the other provider.