How to configure automatic synchronization of other GMX calendars with Mozilla Thunderbird

    1. Start Mozilla Firefox and enter the path https://caldav.gmx.com/your GMX email address in the address line. Press Enter.
    2. Enter your GMX email address and password.
    3. Click Home collection at the end of the page.
    4. Right-click the name of the calendar you want to synchronize with Thunderbird.
      A context menu opens.
    5. Select Copy Link Location in the context menu.
    6. Start Mozilla Thunderbird.
    7. Click on the menu icon in the top right corner of the Thunderbird window.
    8. In the New submenu, select Calendar.
    9. Select the On the Network option and then Next to continue.
    10. Select the CalDAV format.
    11. Click the Location field and press Ctrl + V to paste the link address of the calendar from the clipboard.
    12. Click Next.
    13. Give the GMX Organizer a name and, if applicable, a color. Appointments from this calendar will later be displayed in the color. Select Next to continue.
    14. Complete setup by clicking Finish.
    Next step:

    If you want to synchronize other GMX Organizers with Thunderbird, repeat steps 4 through 14.