Caldav sync with Horde Groupware

I am currently evaluating em Client and I am running into the following problem. 
We are using a Horde Groupware instance to synchronize calendars and address books via CalDav and CardDav. 

After setting up a Calendar/Contact account and point it at the horde server the calendars and address books are correctly discovered (and the address books work fine), but as soon as em Client start synchronizing we get the following error: 

15:24:28 [CalDAV / CardDAV] Synchronisiere Elemente: Die Synchronisation vom Element /rpc.php/calendars//calendar:LivF4OKsiACgZju4Bd317w4/b90701d9-d92d-4dd9-9d24-965f193e43b0-caldavsyncadapter.ics ist fehlgeschlagen, durch folgenden Fehler: DTSTART

The error message is in German so the gist of it is 

Synchronizing Elements: The Synchronization of Element … failed, because of error: DTSTART

So the entries in the calendar get sync back to the server but only a few entries are synchronized down. Our mobile clients, mostly Android based synchronize just fine also via CalDav.

Also task seem to work right out of the box.

Our Horde setup is v5.2.3 with kronolith at 4.2.3 an we use em Client 6.0.21040

If you need any more informations, please let me know.


Hi Valentin, can you please navigate to Tools > Settings > Advanced and turn on CalDAV/CardDAV logging for the problematic account?

  1. Save the settings
  2. Restart the application
  3. Replicate the issue
    Once the issue reoccurs, please go back to the advanced settings window and click on “Send logs” and send the logs to my email with a reference link to this forum topic.

Thank you,