Hi, I have a similar problem since two days.
I am using iOS 16.6 Public Beta and the Apple Calendar App. The app shows the error message “Unable to update calendars.” for my mailcow account. I tried to remove and add the iOS Profile and it worked for a day. But now it is broken again.
The Apple Mail App works perfectly using the iOS profile. And the Apple Contacts App does not show any errors, too.
These are the only corresponding entries I could find in the SOGo logs:
08/08/2023, 21:50:58 notice [75]: 2a04:****:****:****:****:****:****:e264 "REPORT /SOGo/dav/***%40***.de/Calendar/personal/ HTTP/1.0" 207 288/462 0.010 - - 0 - 14
08/08/2023, 21:50:58 notice [75]: [ERROR] <0x5619655fee00[SOGoAppointmentFolder]:personal> DAV property '{http://calendarserver.org/ns/}created-by' has no matching SQL field, response could be incomplete
08/08/2023, 21:50:58 notice [75]: [ERROR] <0x5619655fee00[SOGoAppointmentFolder]:personal> DAV property '{http://calendarserver.org/ns/}updated-by' has no matching SQL field, response could be incomplete
08/08/2023, 21:50:58 notice [75]: [ERROR] <0x5619655fee00[SOGoAppointmentFolder]:personal> DAV property '{urn:ietf:params:xml:ns:caldav}schedule-tag' has no matching SQL field, response could be incomplete
08/08/2023, 21:50:58 notice [75]: 2a04:****:****:****:****:****:****:e264 "REPORT /SOGo/dav/***%40***.de/Calendar/personal/ HTTP/1.0" 401 0/462 0.002 - - 0 - 13
08/08/2023, 21:50:58 notice [75]: 2a04:****:****:****:****:****:****:e264 "REPORT /SOGo/dav/***%40***.de/Calendar/personal/ HTTP/1.0" 207 713/234 0.027 - - 0 - 13
08/08/2023, 21:50:58 notice [75]: 2a04:****:****:****:****:****:****:e264 "REPORT /SOGo/dav/***%40***.de/Calendar/personal/ HTTP/1.0" 401 0/234 0.001 - - 0 - 13
08/08/2023, 21:50:58 notice [75]: 2a04:****:****:****:****:****:****:e264 "PROPFIND /SOGo/dav/***%40***.de/Calendar/ HTTP/1.0" 207 1576/2237 0.086 12390 87% 3M - 13
08/08/2023, 21:50:57 notice [75]: 2a04:****:****:****:****:****:****:e264 "PROPFIND /SOGo/dav/***%40***.de/Calendar/ HTTP/1.0" 401 0/2237 0.003 - - 0 - 12