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⚠️ Critical Issue

Postmark Emails Going to Spam: Diagnosis & Fixes for Postmark Senders

Your Postmark transactional or marketing emails are landing in spam

Fix within 24 hours.

Check your Postmark configuration:

1

In Postmark, verify your sending domain is added and confirmed

2

Check DKIM and SPF are configured correctly

3

Review Postmark bounce and spam complaint metrics

What Could Be Causing This?

Postmark Domain Not Fully Verified

Most Common
InboxEagle Detects This ✓

Postmark requires full domain verification with DKIM and SPF.

How to confirm:

In Postmark, check if domain shows all verification checks as passed.

Fix Playbook

Step 1: Fully Verify Your Domain in Postmark

HoursImpact: High
  1. In Postmark, add your sending domain
  2. Complete DKIM configuration
  3. Add SPF record
  4. Verify Return-Path CNAME (Postmark specific)
  5. All checks must pass for reliable delivery

Postmark-Specific Note:

Postmark requires Return-Path CNAME setup — this is not needed by other ESPs but critical for Postmark.

Prevention Checklist

  • Keep Postmark domain fully verified
  • Monitor bounce and spam complaint rates

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Frequently Asked Questions

What is Postmark Return-Path CNAME?
Return-Path CNAME is Postmark's bounce handling mechanism. Required for full authentication.
Free Checklist

The exact checklist used by 2,000+ email senders to diagnose and fix inbox placement issues — free.

  • Authentication setup (SPF, DKIM, DMARC)
  • Sender reputation signals to monitor
  • List hygiene benchmarks
  • Content & engagement red flags

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