An engineer in a company have access to voice calling and voicemail from desktop phones As the company transitions to remote work, users are…

For Mobile and Remote Access (MRA) to function, the Expressway-C must be configured with the addresses of all internal Unified Communications (UC) application servers that remote clients need to access. While calling and presence are working, indicating CUCM and IM & Presence servers are correctly configured on Expressway-C, the failure of voicemail access for Jabber MRA clients points to a missing configuration for Cisco Unity Connection. Expressway-C acts as a proxy for these services; without the Unity Connection server defined in its configuration, it cannot proxy the voicemail requests from external Jabber clients, causing the service to fail.

A. Cisco Unity Connection is missing from the internal Cisco UCM mobility profiles Mobility profiles in CUCM are primarily used for the Mobile Connect feature (Single Number Reach), not for providing Jabber clients with access to visual voicemail services.
C. Cisco Unity Connection is missing from the internal Cisco UCM clusters. This is incorrect because the scenario states that voicemail is functioning correctly for users on their desk phones in the office, which confirms that Unity Connection is already integrated with CUCM.
D. Cisco Unity Connection is missing from the Expressway-E clusters for external communication. Internal application servers like Unity Connection are configured on the Expressway-C. The Expressway-E handles external client connections and does not have direct configuration pointing to internal UC servers.

1. Cisco Expressway Administrator Guide (X14.2)

Page 121

"Unified Communications Servers for MRA" section.

The guide states

"The Expressway-C must be able to route requests to the appropriate Unified Communications servers... You must add any Cisco Unity Connection... servers that you want to make available to MRA clients." This directly supports that Unity Connection must be added to the Expressway-C configuration for MRA voicemail to work.

2. Mobile and Remote Access Through Cisco Expressway Deployment Guide (X14.0)

"Add Other Unified Communications Servers to Expressway-C" section.

This guide provides the specific procedure: "On Expressway-C

go to Applications > Unified Communications > Unified CM servers... Click New to add the Unity Connection server details." This confirms that the configuration is performed on Expressway-C

making option B the correct answer.

3. System Configuration Guide for Cisco Unified Communications Manager

Release 12.5(1)

"Voicemail" chapter

"Voicemail Server" section.

This document details the integration of Unity Connection with CUCM. The fact that desk phones can access voicemail

as stated in the question

implies this basic integration is already complete

invalidating option C.