I have the following situation:
User (GroupWise) send an appointment to an external System (Exchange). If the external User decline/accept the appointment, the Exchange Server send back an Decline/Accept Message to the Sender. But the user who have send the appointment, never receives the decline/accept message.
When i look at the GWIA logs, i can see the decline/accept message from the exchange system, but this message never goes to the inbox of the user.
I checked severall settings in GroupWise Client and GWIA, but i cannot find the right one. DSN is enabled.

GroupWise System: 2012 SP2 Build 108211
GroupWiswe Client: 2012 SP2 Build 110465