Call Processing to Messaging System Call Flow

This topic shows the areas where you can start troubleshooting, depending on the issue classification.

Identify the main areas to consider when troubleshooting direct or forwarded calls to voicemail. Focus on the key areas:

  • Cisco Unified Communications Manager Express
    1. Phone configuration
    2. Dial peer to voicemail
  • Cisco Unity Express
    1. Voicemail application
    2. Subscriber configuration

When you troubleshoot, it is a good idea to identify the main areas and to focus on the key components. A detailed understanding of the sequence of events is also useful. Looking in depth at a specific area may not be helpful. For example, consider a situation where voicemail calls do not arrive at Cisco Unity Express. Detailed Cisco Unity Express troubleshooting is not necessary because the problem area must be located somewhere earlier in the sequence of events—perhaps in Cisco Unified Communications Manager Express. To troubleshoot calls that are forwarded to voicemail, the key areas are as follows:

  • Cisco Unified Communications Manager Express
    1. IP phone configuration: Is the phone configuration correct and are the phones correctly registered? Changes for SIP phones require creating new configuration profiles and a reset of the phones.
    2. Voicemail dial peer: The dial peer for voicemail has certain requirements: for example, SIP, DTMFsettings, and the codec G.711.
  • Cisco Unity Express
    1. Voicemail application: The trigger number must be set up, and it must match the destination pattern on the dial peer to be able to accept the calls. There must be enough sessions available to the application to prevent call blocking.
    2. Subscriber configuration: The user must be configured with a mailbox. The mailbox must be enabled and unlocked.


In this section, we describe how to troubleshoot issues within a Cisco Unity Express voicemail solution by using Cisco Unified Communications Manager Express as the call-processing system.