Refer to the exhibit. Calls to Cisco Unity Connection are failing across Cisco Unified Border Element when callers try to select a menu prompt. Why is this happening and how is it fixed?

When callers cannot select menu prompts in Cisco Unity Connection, it is almost always a DTMF (Dual-Tone Multi-Frequency) signaling issue. The Cisco Unified Border Element (CUBE) must be explicitly configured on its dial-peers to support a DTMF relay method, such as rtp-nte (RFC 2833) or sip-kpml, to ensure that the touch-tones pressed by the caller are correctly transmitted to and recognized by Unity Connection. Without proper DTMF configuration on CUBE, the user input will not reach the voicemail system.

A "Release to Switch" transfer type in Unity Connection affects how calls are transferred after a menu selection, not the ability for callers to make selections from the menu itself.

While codec mismatches can prevent calls, a G.729-only configuration on Unity Connection would cause call failure due to audio incompatibility, not specifically when trying to select a menu prompt, as audio must first be established to hear the prompt.

If CUBE were sending an incorrect media IP address, the media path would fail, and callers would not hear prompts or experience a quickly dropping call, rather than successfully reaching prompts but being unable to select options.