Perform these steps to configure email notification for the CUE users:
Go to Voicemail > Message Notification > Notification Administration and perform these steps:.
Go to Administration > Domain name settings > set your domain name (mycompany.com) and set your DNS server if you have one. Click Apply.
Go to Administration >SMTP Settings > Set your SMTP server address, as well as any authentication if needed. Click Apply.
Go to Configure > User > choose user > check the Enable notification for this user box at bottom of the screen. Click Apply.
Go to Configure > User > Notification tab > click on email inbox. Perform these steps:
On the router, set your domain-name and ip name-server.
Sourced from the thread https://supportforums.cisco.com/thread/2028219?tstart=0
Good document. Cisco document missed step 4. The Enable notification to this device is grey out in the Notification Tab if this step is missing.