hello, we are running calendar server on Mac OS X Server 10.7.4 (Build 11E53) clients: Mac OS X 10.6.8, 10.7.5, 10.8.2, and iOS5, iOS6 sometimes, if someone receive a "external" invitation per mail attachment (*.ics file) and try to add this event in iCal, the server responds with an error message: The server responded with an error. Access to "event-name" in "calendar-name" in account "account-name" is not permitted. The server responded: "403" to operation CalDAVWriteEntityQueueableOperation. i can reproduce this behavior when I create a event in a "local" calendar in iCal and invite an attendee per mail/ics-file and the receiver try to add this event in iCal on Mac OS X 10.6.8 (in this case this error didn't appear on 10.7 or 10.8) following entry appears in caldavd error.log: 2012-11-14 12:29:44+0100 [-] [caldav-7] [PooledMemCacheProtocol,client] [twistedcaldav.method.put_common#error] Attendee cannot create event for Organizer: 2 can someone explain why this happen or how we can avoid this error when getting invitations from external or per mail/*.ics-file ?