Users report that they are unable to check voicemail, and an engineer discovers that the voicemail system is not routing calls between Cisco Unity Connection and Cisco UCM via SCCP. Which action should be taken to resolve this issue?
A. Verify voicemail SIP trunk in the route list.
B. Verify OPTIONS Ping in the SIP trunk profile.
C. Verify registration of the CTI ports.
D. Verify Calling Search Space in the Directory Number setting.
