Core Issue
This issue occurs because of the protocol incompatibility with the call state of Cisco Unity.
When this issue occurs, the Error message Cause i = 0x80E5 - Message not compatible with call state error message appears.
Resolution
In order to resolve this issue, uncheck Display IE Delivery in the H.323 gateway configuration page in the Cisco CallManager.
Note: The public switched telephone network (PSTN) does not support Display IE in q.931 messages.
Refer to the Display IE section of CallManager CallerID Feature Issues for more information on the Display IE Delivery option.