When I run the Message Delivery Audit report there is no data in the report
Auditing for message delivery times is not enabled.
To set a delivery time threshold for traffic within sites
1. Expand the Exchange Organizations node in the tree view and select an Exchange organization.
2. Right-click and select Properties.
3. Select the Delivery Time Audit tab.
4. Select the Enable message delivery time auditing box
You can audit messages that take an unusually long time to be delivered to the recipients. Using the Delivery Time Audit tab, you can enable message time auditing and set a threshold for message delivery times.
When a message takes longer to deliver than the audit threshold, it is reported in the Message Delivery Audit report in MessageStats Reports under the Servers | Delivery Times
Option: Threshold value for delivery time in Exchange organization (in seconds)