The user does not have an Exchange mailbox
Applies to: Exchange Server 2013
This error indicates that you may be attempting to move a mailbox between databases or servers, and the move request is failing. You could see this error if the user was recently mailbox enabled and all properties have not been replicated in Active Directory.
To resolve this error, do one or more of the following:
Check to see if the user was recently converted to a mailbox enabled user
Wait for Active Directory replication to occur in your forest
Note
The amount of time that replication takes depends on your Active Directory site topology.