Background: When a calendar meeting is created, an automated message is send to all the attendants, required to be there, requesting a response of either accepting, rejecting, etc. the meeting.
When the attendant accepts the invitation it should update both his/her calendar and the meeting organizer's calendar to reflect this response.
Issue 1: Mail Client: Thunderbird (Attendant)
When accepting the invitation received in the Thunderbird inbox, no reply is send to the organizer's inbox. The organizer's calender indicates that the attendant still needs to respond to the invitation. The attendants calendar also shows that the attendant has not yet accepted the invitation. (A more in depth investigation by looking at the meeting schedule, confirms this).
Issue 2: When trying to accept the meeting again using the same email received in the Thunderbird inbox and error with the following details appear:
Invitation could not be processed. Status: 2152333316 Details: ID exists for addItem
The option to accept, reject, etc. then disappears, but reappears when the message is reopened.
Issue 3: When the attendants mailbox is opened using Outlook 2003 and the same message mentioned above is accessed, after the previous attempts have been made, the attendant is again given the option to either accept, reject, etc. the invitation. Upon accepting the invitation, the options are given to send either an edited response, normal response or no response at all. Choosing normal response, the message disappears from the inbox and reappears in the send folder. The organizer receives an email indicating the invitation is accepted and both the organizer and the attendant's calendar reflects this response.
Issue 4: Mail Client: Outlook 2003 (Attendant)
If the attendant accepts the invitation received in his/her Outlook inbox, without implementing the previous steps mentioned in Issues 1 - 3, and sends a normal response, the message is again removed from the inbox and added to the send folder. The organizer receives the response in his inbox, but his/her calendar does not reflect this response and still states that a response is required from the attendant. The attendant's calendar on the other hand does show that the attendant has accepted the invitation.
Finding 1: Mail Client: Zimbra web console (Attendant)
If the attendant accepts the invitation for the first time using his/her Zimbra web console, a reply is automatically send to the organizer's inbox and both the attendant and the organizer's calendars are updated to reflect the response (In other words, it works perfectly when using this approach).
Finding 2: Mail Client: Zimbra web console (Attendant)
Finally, if the attendant accepts the invitation for the first time by first browsing to his/her Zimbra calender, right-clicking on the meeting and then selecting accept, a response is send to the organizer's inbox and both the attendant and the organizer's calendars reflect the response to the invitation. (In other words, it also works perfectly when using this approach)