An Engineer is configuring Cisco Unified Communications Manager (CUCM) version 10.0. The office manager of a remote office to set up a new phone that contains the MAC address of the phone (0AFC00021AB2) and extension 2324. The engineer manually creates a new Cisco unified IP phone 7942 in CUCM, But the phone displays "Registration Rejected" when user plugs the phone in to the LAN.
What should be done to fix this issue if auto registration is already enabled in CUCM?
A. Verify that the phone model being connected is the same type that is configured in CUCM
B. Check the MAC address to make sure that it matches and that there are no extra characters in the MAC address field
C. Ensure that the phone extension is not already used on another set
D. Check the Enterprise License Manager to ensure that the system is not out of licenses
