Summary
Fixing DMARC issues when using multiple sending platforms like Mailchimp and Woodpecker, alongside Office 365, requires careful attention to your DNS records. Common problems stem from incorrect SPF records, unverified DKIM setups, and DMARC policies that conflict with sending practices. The core challenge often lies in ensuring proper alignment between your domain's authentication records and the various sending services.
Key findings
- DKIM verification: A common culprit for DMARC failures is unverified or incorrectly configured DKIM records for each sending service.
- SPF record accuracy: Incorrect SPF records, especially when including multiple services, can lead to authentication failures. You need to ensure all legitimate sending sources are authorized.
- DMARC policy: Starting with a p=none DMARC policy allows for monitoring without immediately blocking emails, which is useful during troubleshooting. For more detail, read our guide on simple DMARC examples.
- DNS management: When a third-party agency manages DNS, coordination is critical to ensure timely and accurate record updates.
- DMARC alignment: For DMARC to pass, either SPF or DKIM must align with your From domain. This often means setting up custom DKIM for ESPs like Mailchimp.
Key considerations
- Custom DKIM for ESPs: Always set up custom DKIM with your email service providers (ESPs) like Mailchimp and Woodpecker to ensure DMARC alignment. This is a critical step for successful email authentication and deliverability.
- SPF record limits: Be mindful of the 10-lookup limit for SPF records. Consolidate includes where possible. If your emails are failing, learn how to troubleshoot and fix SPF and DMARC settings.
- Outlook SPF inclusion: If you send emails directly from Office 365, or an ESP connects via O365 (like Woodpecker), ensure include:spf.protection.outlook.com is in your SPF record.
- Monitoring DMARC reports: Use DMARC aggregate reports (rua) to identify all sending sources and their authentication status. This data is invaluable for troubleshooting.
- DNS propagation: Allow sufficient time for DNS changes to propagate globally (up to 48 hours) before retesting. Tools like Kinsta's DMARC fail guide can help check status.
What email marketers say
Email marketers often face significant DMARC challenges when integrating multiple sending platforms. The consensus among marketers points to the critical importance of custom DKIM setup for each platform, especially for marketing ESPs like Mailchimp, to ensure proper DMARC alignment and prevent emails from failing authentication checks. They also highlight the need for clear communication with DNS providers.
Key opinions
- Custom DKIM is a must: Many marketers stress that setting up custom DKIM for each ESP is essential to fix DMARC issues. Without it, emails sent through these platforms will likely fail DMARC alignment.
- SPF record complexity: Integrating multiple sending services means the SPF record can become complex and prone to errors. It's crucial to list all legitimate senders correctly, even though for DMARC alignment, DKIM is often the preferred method with ESPs like Mailchimp.
- Prioritize DKIM for alignment: While SPF is important, for DMARC alignment with third-party senders, custom DKIM is typically more effective, as it signs the email with your domain, ensuring alignment.
- Temporary DMARC policy: Changing a DMARC policy to p=none provides a safety net while troubleshooting authentication issues, preventing legitimate emails from being blocked.
Key considerations
- Verify each sender: Ensure every email sending service (Mailchimp, Woodpecker, Brevo) has its DKIM records correctly configured and verified in your DNS. Mailchimp has specific guidance on email domain authentication.
- DNS management challenges: If a third party manages your DNS, provide them with precise instructions and verify changes promptly. Errors or delays here can significantly impact deliverability.
- Office 365 integration: Since Woodpecker connects via O365, the spf.protection.outlook.com inclusion in SPF is necessary. Also, ensure that DKIM signing for your custom domain in O365 is set up correctly.
- DMARC reporting: Leverage DMARC aggregate reports (RUAs) to get visibility into your email traffic and identify sources of authentication failures. These reports help diagnose issues even with a p=none policy.
Marketer view
Email marketer from Email Geeks suggests setting up custom DKIM for Mailchimp, stating that this specific action should resolve common DMARC issues. They imply that the lack of proper DKIM configuration is a primary cause for DMARC failures, especially with third-party ESPs. This is a crucial step to achieve DMARC alignment.
Marketer view
A marketing manager from a Deliverability Forum explains that when using multiple senders, even if SPF seems correct, DKIM alignment is key for DMARC. They advise checking each ESP's specific DKIM setup instructions, as generic solutions often fall short. They emphasized the importance of ensuring the signing domain matches the From domain.
What the experts say
Experts in email deliverability emphasize that SPF and DKIM authentication are foundational for DMARC compliance, especially when using multiple sending services. They consistently advise on the necessity of custom DKIM for ESPs to achieve DMARC alignment. Furthermore, they highlight that DMARC reports are invaluable for identifying misconfigurations and ensuring all legitimate sending paths are properly authenticated.
Key opinions
- Custom DKIM for alignment: Experts reiterate that for DMARC alignment, especially with ESPs, setting up custom DKIM is paramount. This allows the sending domain to match the From address of the email.
- SPF record accuracy: While Mailchimp often passes SPF on its own domain, ensuring your main domain's SPF includes Office 365 (if sending via it, like Woodpecker) is crucial for those mail streams. Consult our guide on why you shouldn't add Mailchimp to SPF records.
- DMARC policy evolution: Starting with p=none is a responsible way to deploy DMARC, allowing for data collection before moving to more restrictive policies like p=quarantine or p=reject.
- Comprehensive auditing: A holistic audit of all email sending paths is necessary. Missing even one legitimate sender in your authentication records can lead to deliverability issues.
Key considerations
- DNS propagation delays: Be patient with DNS changes. Propagation can take hours, even with a fast DNS provider like Cloudflare. Premature retesting can lead to false negatives.
- Verify CNAME accuracy: When adding DKIM records as CNAMEs, ensure the host/name and value are exact matches to what the ESP or O365 provides. Typos are common. This is critical for fixing common DMARC issues.
- Monitoring and iterative adjustments: DMARC is not a set-it-and-forget-it solution. Continuous monitoring of reports and making iterative adjustments to your authentication records are essential for long-term deliverability.
- Understand ESP authentication nuances: Each ESP handles authentication slightly differently. Understand whether they rewrite the Return-Path (affecting SPF alignment) or require custom DKIM for full DMARC compliance.
Expert view
Email deliverability expert from Email Geeks clarified that the SPF record for Mailchimp actually uses Mailchimp's own domain. This means that while SPF might pass for Mailchimp's domain, DMARC alignment for your From domain requires custom DKIM setup. This is a common point of confusion for those new to DMARC.
Expert view
A deliverability consultant from Word to the Wise suggests that DMARC issues with services like Woodpecker integrating with O365 often stem from misconfigured DKIM on the Office 365 side itself. Even if the ESP provides instructions, the final setup and verification in Azure/Defender portal are paramount for success.
What the documentation says
Official documentation from email service providers and standard bodies (like RFCs) provides the authoritative guidelines for DMARC, SPF, and DKIM configuration. They outline specific records required for authentication, emphasizing the need for accurate DNS entries. Documentation typically details how to generate and publish CNAME records for DKIM and TXT records for SPF and DMARC, crucial for ensuring emails pass validation checks across different platforms.
Key findings
- Canonical Name (CNAME) records: Documentation for ESPs often instructs users to add specific CNAME records to their DNS for DKIM setup. These records point to the ESP's signing keys, enabling them to sign emails on your behalf.
- SPF TXT record format: The SPF record is a TXT record starting with v=spf1 and includes all authorized sending IP addresses or domains. The -all mechanism is a strong policy indicating unauthorized senders should fail.
- DMARC TXT record format: DMARC records are also TXT records, typically at _dmarc.yourdomain.com. They specify the policy (p=none, p=quarantine, p=reject) and where to send reports.
- DMARC alignment rules: DMARC requires either SPF or DKIM to align with the From domain. This means the domain used in the SPF Return-Path or the DKIM d= tag must match your organizational From domain (either exact or relaxed).
Key considerations
- Mailchimp DKIM setup: Mailchimp's documentation explicitly requires users to set up custom domain authentication (DKIM) to ensure DMARC compliance. This involves adding two CNAME records provided by Mailchimp to your DNS. More details can be found in our article on how to implement DMARC safely.
- Office 365 DKIM configuration: Microsoft 365 documentation details how to enable DKIM for your custom domains through the Defender Portal or PowerShell. This is crucial for emails sent directly from O365 or via applications like Woodpecker that relay through O365.
- SPF 10-lookup limit: RFCs specify that an SPF record should not involve more than 10 DNS lookups. Exceeding this limit will cause SPF to fail, even if includes are correct. This is a common issue when integrating many services.
- DMARC report analysis: DMARC's reporting mechanisms (rua and ruf) are designed to provide visibility into authentication results, helping diagnose failures. Understanding these reports is key. Our guide on troubleshooting DMARC reports can help.
Technical article
Mailchimp's documentation states that to verify a domain for sending, you must authenticate it using DKIM. They specify that this process involves adding two CNAME records to your domain's DNS settings. This authentication helps improve deliverability and ensures your emails comply with DMARC policies set by receiving servers.
Technical article
Microsoft 365 support articles outline the steps to enable DKIM for your custom domain in Exchange Online, noting that this is essential for email spoofing protection. They provide specific PowerShell commands or instructions via the Defender portal to generate and publish the necessary CNAME records. Correct setup ensures outgoing emails from O365 are signed and verifiable.
Related resources
2 resources
Related pages
How do I troubleshoot and fix SPF and DMARC settings for email deliverability issues?
How do I fix DKIM alignment errors and configure DKIM signing for a custom domain in Microsoft 365 and is include:spf.mtasv.net required for mailchimp?
A simple guide to DMARC, SPF, and DKIM
How to fix common DMARC issues in Microsoft 365 and Google Workspace
Why you shouldn't add MailChimp to your SPF record
How to safely transition your DMARC policy to quarantine or reject
How to implement DMARC p=reject policy safely, especially when using ESPs like Mailchimp and GetResponse?
Understanding and troubleshooting DMARC reports from Google and Yahoo
Why your emails fail: expert guide to improve email deliverability [2025]
Boost email deliverability rates: technical solutions from top performing senders
