Nextcloud CalDav sync problem - Invalid Format

Hi everybody,
I tried to find similar topics here, but unfortunately to no avail. Many people seem to successfully use Nextcloud calendar with emClient. (Which is great and I’m planning to do that as well :wink:)

Here’s my setup:
Nextcloud 22.2.0 on managed server
Created a user, added the calendar app. I’m using the empty “personal” calendar.
Got the private link from nextcloud, in emClient went “Tools” - “Subscribe to Internet Calendar”, pasted URL and filled in Username and Password.

Then I get the following error:
[Web Calendar]Synchronizing folder 'Internet Calendars/https://XXX.your-storageshare.de/remote.php/dav/calendars/USER/personal/' failed due to the following error: One of the identified items was in an invalid format.

Full error log:
15:57:02 Internet Calendars Web Calendar Synchronizing folder '/https://XXX.your-storageshare.de/remote.php/dav/calendars/USER/personal/'
15:57:05 Internet Calendars [Web Calendar] MailClient.Storage.Application.OperationException: Synchronizing folder 'Internet Calendars/https://XXX.your-storageshare.de/remote.php/dav/calendars/USER/personal/' failed due to the following error: One of the identified items was in an invalid format.

  ---> System.FormatException: One of the identified items was in an invalid format.
                at MailClient.VObject.CalendarReader.LoadCalendar(Calendar calendar)
                at MailClient.VObject.Calendar..ctor(TextReader reader)
                at MailClient.Protocols.WebCal.WebCalCalendarSynchronizer.Synchronize(IItemSynchronizeContext1 synchronizeContext, Folder folder, CancellationToken cancellationToken)
            at MailClient.Protocols.Common.ItemSynchronizer2.<>c__DisplayClass37_1.<EnqueueSynchronize>b__6(WorkerStatus status, CancellationToken ct)
            at MailClient.Protocols.WebCal.WebCalGenericCommand.Execute(WorkerStatus status)
            --- End of inner exception stack trace ---
           GUIStatus_Exception_Reported = True

Syncing the calendar with Thunderbird works just fine. Strange is that the calendar is currently empty, so I’m not quite sure which item could have an invalid format. Maybe someone can help?

All the best
Olav

Edit: I’m using eMClient version 8.2.1659