I use a caldav calendar which is operated by my email provider (Ionos). The connection / entry / removal of appointments works perfectly. However, invitations/cancellations/etc. are only sent by the caldav server, but unfortunately in such a way that the appointments/changes cannot be accepted directly in the client (accept button missing, for example). The behavior does not change even if the option "Prefer client-side email scheduling" is activated in the calendar settings. If I use a local calendar, everything works fine, Thunderbird then sends its own notifications, which I can also track in the outbox folder. How can I get Thunderbird to send the "normal/own" notifications for caldav calendars?