You have an Exchange Server 2013 organization that has Unified Messaging (UM) deployed. You configure a customized business hours greeting by using the Exchange Admin Center.
Users report that the custom greeting fails to play when a call is received by UM. You need to identify the most likely cause of the issue.
What should you identify?
A. A Microsoft Exchange Unified Messaging service stopped.
B. A Microsoft Exchange Unified Messaging Call Router service stopped.
C. A system mailbox was deleted.
D. The DiscoverySearchMailBox was deleted.
