With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccmVMailDevRegFailReason
Cisco Call Manager V Mail Device Registration Fail Reason
1.3.6.1.4.1.9.9.156.1.12.1.1.13
The reason code associated with registration failed Voice Messaging Device.
Back to CISCO-CCM-MIB MIB page.
IPHost Network monitor allows you to monitor ccmVMailDevRegFailReason on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.