eGroupware CalDav - Read Only Problem

Hi Guys,

I realy like One Calender and would like to recommend it to all of my collegues.

Unfortunatly there is an issue with our "eGroupware" Caldav sync. One Calendar only supports read only for this, I'm not able to create any new entrys. The eGroupware-credentials are working fine with writing access for other Calendars (Thunderbird, Android, ...), but not in One Calendar.

I'm also able to connect other caldav - calendars with writing support to One Calendar.