When integrating an AudioCodes gateway with Microsoft Exchange Unified Messaging, you may see an issue where the call is terminated while someone is leaving a voicemail longer than 30 seconds. This is because the gateway assumes the connection is broken the moment you start speaking, since UM is no longer sending RTP packets or silence suppression codes.

The solution is to turn of the Disconnect on Broken Connection on the IP profile used for your UM server within the AudioCodes gateway.