Mailbox reports were working but are now blank.
The mailbox gathering task is failing.
1. In the MessageStats Console expand Exchange Organizations, right click on your organization and select properties.
2. Click the Connection Server tab.
3. Check to make sure the server defined as the connection serve is online and responding. If you have recently upgraded you Organization to 2010 you will need to use the 2010 section of the Connection Server tab and define a 2010 CAS server and logon mailbox to which the service account has full access.