Core Issue
The user receives this error message in the Cisco CallManager traces:
12/13/2004 19:11:57.822 CCM
Resolution
This issue is tracked in Cisco bug ID CSCeg54958.
For a workaround configure a call forward option on that Directory Number (DN).
If you configure any of the call forward options for that DN (whether by checking the voice mail checkbox or entering a DN), you can then call the Message Waiting Indication (MWI) on/off numbers. The lamp is lit or unlit.
For more information, refer to Configuring Directory Numbers.