Message Trace

Message trace is the Exchange Online admin tool for tracking the path of an individual email message through the delivery pipeline. For each traced message, admins see every event: received, scanned by EOP, evaluated against transport rules, delivered, failed, deferred. Searchable by sender, recipient, subject, date range, status, and message ID. The first stop when diagnosing "I didn't receive that email" or "the email I sent never arrived" issues. Available in the Exchange Admin Center (recent searches, up to 7-day history) and via the Get-MessageTrace / Get-MessageTraceV2 PowerShell cmdlets for deeper investigation. Historical traces (older than 7 days) require Historical Search via PowerShell.