The internal health monitoring system may report Unhealthy, and an error similar to the following is reported by SCOM:

Alert: {2} Resolution state: New

Alert: {2}
Source: EXCH02 - Compliance
Path: EXCH02.contoso.com;EXCH02.contoso.com
Last modified by: System
Last modified time: 9/3/2015 11:43:37 AM Alert description: EMSMDB.DoRpc(Logon) step of ComplianceOutlookLogonToArchiveRpcCtpProbe/EXCHDB03 has failed against EXCH02.contoso.com proxying to Unknown for HealthMailbox8414258ad6574db1ad62eb67e94b9d6d@contoso.com.
Latency: 00:00:00.9250000
ActivityContext:
.
.
.
Details:
Error: Error returned in LogonCallResult. Error code = WrongServer (0x00000478)
Log: RpcProxy connectivity verification

This is usually caused by invalid HealthMailboxes (e.g. health mailboxes that no longer exist or have been moved because a database has changed).

You can attempt to resolve the situation, but it's probably more easier to simply let the Exchange Health Monitor re-create the HealthMailboxes.

1. On each Exchange mailbox server, stop the Microsoft Exchange Health Manager service:

   net stop MSExchangeHM

2. Remove all HealthMailbox accounts in Active Directory.
   They are in the Microsoft Exchange System Objects/Monitoring Mailboxes container.
3. On each Exchange mailbox server, start the Microsoft Exchange Health Manager service:

   net start MSExchangeHM

   The mailboxes will be re-created in a few minutes after the service has been started.