Refer to the exhibit. An H.323 endpoint that is registered to Cisco VCS Control is not able to make B2B calls. Calls to other internal endpoints are working fine. What is the likely cause of the…

The Conductor zone handles conferencing resource allocation through Cisco TelePresence Conductor and disabling it would affect conference bridging, not basic B2B point-to-point calls.

B2B (business-to-business) calls traverse the network boundary via the Traversal Zone, which links Cisco VCS Control to VCS Expressway. If the Traversal Zone's H.323 mode is set to 'Off,' the VCS Control cannot route calls outside the local network, while internal H.323 registrations and calls remain unaffected. Disabling only this zone precisely matches the symptom of internal calls succeeding while external B2B calls fail.

The Production CUCM H.323 zone controls communication with Cisco Unified Communications Manager; setting it to 'Off' would prevent calls to CUCM-registered endpoints, not all B2B calls.

A 'Failed' state indicates a connectivity or configuration error preventing communication on that zone, which is a different condition from 'Off' (administratively disabled); the question specifies a deliberate setting, not a failure.