Trying to find out why some messages not reach to users' mailboxes. Searching in Exchange 2000 Message Tracking Center, the message found. When clicking on it, it shows 2 events: 1. Advanced Queue Failed to Deliver Message 2. Non-Delivered Report (NDR) Generated How to see the details of these 2 Events to find out why failed to deliver? From: and To: are all active email addresses.