300-820 practice - PrepKeys

Q5 Single choice

An engineer learns from an end user that calls from outside the company are not being received. Calls are being made to other businesses outside of the company on video using URL addresses. The change management log shows no changes in the configuration of the collaboration solutions. The engineer examines the endpoint, which seems to be registered to the Cisco UCM, and the SIP trunk between the Cisco UCM and sees that the Expressway is also up. In addition, the traversal link shows no errors between the Expressways.

Which action must the engineer take to troubleshoot this issue?

A
On the Cisco UCM, run the Real-Time Monitoring Tool to see if any incoming calls fail.
B
On the Expressway-E, run diagnostic logging under maintenance to see if any requests reach the system.
C
On the Expressway-E, check the NTP settings to ensure that TLS will be able to terminate. If the clock is out of sync, incoming calls from other working systems would work bur not outgoing calls from the company.
D
On the Expressway-C, run a network log under administrative tools to see if any requests reach the system.