Postmark DMARC digest flags Mailchimp SPF failures: expected, not a DNS bug

Not specified by the original author.

TL;DR

The only full fix is DKIM alignment or a sender that supports a custom Return-Path.

Steps

1. If Postmark's DMARC digest flags SPF failures on your Mailchimp mail while your SPF record looks correct, stop editing DNS: it is expected. Mailchimp sends with its own bounce domain and offers no custom Return-Path, so SPF alignment fails by design under DMARC. The only full fix is DKIM alignment or a sender that supports a custom Return-Path. Treat digest SPF failures on Mailchimp-sourced mail as informational, not as a misconfiguration to chase.

When to use

You are seeing this: If Postmark's DMARC digest flags SPF failures on your Mailchimp mail while your SPF record looks correct, stop editing DNS: it is expected. Use this skill when you run into "Postmark DMARC digest flags Mailchimp SPF failures: expected, not a DNS bug".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Stack Overflow #50469686 (answer score 17): A user's DNS looks correct, with Mailchimp's servers in the SPF record, yet Postmark's weekly DMARC digest reports SPF failures on Mailchimp-sent mail. The answer explains this is not a DNS mistake: Mailchimp uses its own domain in the bounce address and does not support a custom Return-Path, so its mail always fails DMARC's SPF alignment test even when the SPF record is right. No DNS change fixes it.

Verified resolution: If Postmark's DMARC digest flags SPF failures on your Mailchimp mail while your SPF record looks correct, stop editing DNS: it is expected. Mailchimp sends with its own bounce domain and offers no custom Return-Path, so SPF alignment fails by design under DMARC. The only full fix is DKIM alignment or a sender that supports a custom Return-Path. Treat digest SPF failures on Mailchimp-sourced mail as informational, not as a misconfiguration to chase.

Source URL: https://stackoverflow.com/questions/50469686