In a Cisco Unified Communications Manager (CUCM) cluster, you receive a Database Communication Error when you attempt to login to the Publisher server. You need to resolve this issue. Which two solutions should you try to resolve this issue?

A.	Revert the changes for hostname or IP address on the Publisher server.
B.	Verify and ensure that the replication is working on all nodes in the cluster.
C.	Restart the DBL service on the publisher.
D.	Modify the hostname for all Subscriber nodes in the cluster.
E.	Reboot all nodes in the cluster.
F.	Restart the DNS service in the cluster.