SOLVED!!! I learned how to back up the GMX-calendar in an ics-file. and the i dared to click "kalender neu erkennen" ("re-recognize calender"?) now everything is fine it would be great, if the manual would be easier for non-technicians like me. lg jochen

Hello, It seems to me like the server can't process some specific event. You can try to set another past event time limit, e.g. 0 days disable past event time limit (set to blank) → this will use PROPFIND instead of REPORT, so the server doesn't need to process the events; but it won't scale that well, especially if the server doesn't support Collection Synchronization copy events from the faulty calendar to a new one (maybe this fixes the event) or – of course – contact GMX about the server problem. Have you already asked GMX support about it?

Danke. Funktioniert. Wer lesen kann ist klar im Vorteil.

Hi @rfc2822, GMX technical support contacted me, saying "please try again" So I did. After a quick simple test (I enabled past event time limit again) all future events in this calendar are still visible. Lets see if this works for ALL calendars AND for events in 2020 and after ... You may want to check this by your own. Thanks to you and GMX. Kind regards, herz_AG

For me, it seems the "temporary server problem" has reappeared about 1 or 2 weeks ago. Since then server replies "Service" upon calling https://kalender.gmx.net/begenda/dav/mail@address.de/calendar Anybody to confirm these issues?