If the voicemail ports are not registered, perform these steps into the TAPI Service Provider (TSP) configuration from the console of the Cisco Unity server, ensuring that it is set up correctly, as shown:
Go to Start > Settings > Control Panel > Phone and Modem Options > Advanced > Cisco Unity-CM TSP > Configure.
Ensure the Cisco CallManager device name prefix is exactly the same as the port names configured for the voicemail ports in Cisco CallManager, with the exception of the 1, 2, 3, 4,... appended to each port.
Ensure the IP address of the primary server is correct. It is better to use an IP address than a name. The TCP/IP port is usually set to the default of port 2000.
Ensure that IP/RTP port base is set to Auto Assign.
For a detailed discussion of the integration of Cisco Unity with Cisco CallManager, refer to the integration configuration guides listed in Cisco Unity Configuration Guides. For an example of each combination of versions, refer to these documents: