Email Deliverability

DMARC Policy Failure

DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on SPF and DKIM to prevent email spoofing. A DMARC failure means neither SPF nor DKIM passed with proper alignment to the From: domain. With p=reject or p=quarantine policies, failing emails are blocked or sent to spam.

Symptoms

  • Legitimate emails rejected or quarantined
  • DMARC aggregate reports showing high failure rates
  • Recipients reporting emails going to spam

Common Causes

  • SPF and DKIM both failing or not aligned with the From: domain
  • Third-party services sending on your behalf without proper delegation
  • Forwarding services modifying the From: header
  • Misconfigured DMARC record syntax

Step-by-Step Troubleshooting

  1. 1

    Check DMARC record

    Validate DMARC record syntax, policy, and reporting configuration.

    Use DMARC Check →
  2. 2

    Validate SPF

    Ensure SPF passes and is aligned with the From: domain.

    Use SPF Checker →
  3. 3

    Validate DKIM

    Ensure DKIM passes and the d= domain aligns with the From: domain.

    Use DKIM Validator →
  4. 4

    Analyze email headers

    Inspect authentication results in email headers to identify which mechanism is failing.

    Use Email Headers →

Recommended Diagnostic Tools

DMARC CheckSPF CheckerDKIM Validator

Monitor DMARC Compliance

Track DMARC authentication results and alignment.

Related Problems

Frequently Asked Questions