End-to-End Email Tracking Simplified

Source: Dev.to

Mail Flow Overview

Mail flow refers to the path an email takes from the sender ➝ through mail servers ➝ security policies ➝ and finally to the recipient’s mailbox.

End-to-End Troubleshooting Approach

Step 1: Start With Message Trace

In Exchange Admin Center, run a Message Trace to instantly confirm:

• Was the mail sent?
• Did it reach Microsoft 365?
• Final status → Delivered / Delayed / Blocked / Failed / Quarantined

Step 2: Verify Mail Status

Check where the message actually landed:

• Delivered to Inbox
• Delivered to Junk/Spam
• Blocked by anti‑spam or transport rule
• Quarantined by security policy

Over 70% of “mail not received” cases end here.

Step 3: Review Exchange Transport Rules & Policies

Invisible blockers are common — especially in enterprise setups:

• Custom mail flow rules
• DLP restrictions
• Anti‑spam configurations
• Allow/Block lists

A new rule change can silently stop important mail.

Step 4: Analyze Message Headers (Most Powerful Step)

Headers are the forensic evidence of email delivery. They reveal:

• Full routing path
• Server hops + delays
• SPF / DKIM / DMARC authentication
• Sender reputation details
• Latency or failure points

Step 5: Don’t Forget External Factors

Sometimes the issue is not Microsoft 365. Examples:

• Sender is blacklisted
• Their domain has DNS errors
• Mail servers throttled / down
• Poor IP reputation