Here some great tools/scripts for message tracking on your exchange server (works for Exchange 2013 and 2016)
Exchange management shell command: Get-MessageTrackingLog -ResultSize Unlimited -Start “Jan 17 2018” | Out-GridView
Microsoft Powershell script: Exchange 2013 Message Tracking Log GUI here (also works on Exchange 2016)
Make sure you turn on Message tracking log on your Exchange server ofcourse.
open ECP -> servers -> servers. choose your mailbox server and edit. Under transport log enable “Enable message tracking log”