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What was the issue with Hotmail's DMARC record and how did it affect email deliverability?

6 Marketer opinions5 Expert opinions3 Technical articles2 Resources

Summary

The issue with Hotmail's DMARC record stemmed from an initial lack of proper DMARC policy publication. This meant that emails failing DMARC checks were not identified as spoofed. Subsequently, some mailbox providers, including Apple iCloud, Yahoo, and Verizon, started rejecting messages based on Hotmail's DMARC entries. The situation was reflected in the DMARC record updating to 'p=none' for a period. In general, incorrect or missing DMARC records at Hotmail/Outlook.com can cause significant email deliverability issues, with legitimate emails being flagged as spam or rejected. Since DMARC is designed to prevent email spoofing, any issues with its configuration can cause messages to fail authentication, resulting in emails being blocked or sent to the junk folder, ultimately disrupting email delivery and negatively impacting sender reputation. The issue appears to have been fixed.

Key findings

  • Initial Lack of Policy: Hotmail initially did not publish a correct DMARC policy.
  • Rejection by Providers: Mailbox providers like iCloud, Yahoo, and Verizon rejected messages due to DMARC issues.
  • Spoofing Vulnerability: Without a DMARC record, emails failing authentication were not identified as spoofing.
  • Deliverability Impact: Incorrect DMARC configuration led to deliverability problems.
  • Flagged as Spam: Legitimate emails were flagged as spam due to DMARC issues.
  • Authentication Failure: Messages failed authentication checks because of DMARC issues.
  • Eventual Fix: The Hotmail DMARC record issue was eventually fixed.

Key considerations

  • DMARC Importance: Proper DMARC configuration is crucial for preventing email spoofing and maintaining deliverability.
  • Policy Enforcement: Enforcement of DMARC policy is vital for successful email delivery.
  • Sender Reputation: DMARC issues can negatively affect sender reputation.
  • SPF/DKIM Integration: DMARC works in conjunction with SPF and DKIM to enhance email authentication.
  • Monitoring: Ongoing monitoring of DMARC records is essential to ensure correct configuration.

What email marketers say
6Marketer opinions

The core issue with Hotmail's DMARC record stemmed from either incorrect configuration or a complete lack of a DMARC policy. This led to various mailbox providers, including Apple iCloud, Yahoo, and Verizon, rejecting emails that appeared to originate from Hotmail. The absence or misconfiguration of DMARC caused legitimate emails to be flagged as spam, negatively impacting sender reputation and overall deliverability, as receiving servers could not authenticate the legitimacy of the emails.

Key opinions

  • Rejection by Providers: Mailbox providers like iCloud, Yahoo, and Verizon were rejecting messages due to Hotmail's DMARC issues.
  • Spam Flagging: Incorrect DMARC setup led to legitimate emails being mistakenly flagged as spam.
  • Authentication Failure: Receiving servers could not authenticate emails claiming to be from Hotmail, due to DMARC problems.
  • Deliverability Impact: DMARC configuration directly impacts the ability of emails to reach recipients' inboxes.

Key considerations

  • DMARC Importance: Proper DMARC configuration is crucial for email authentication and ensuring deliverability.
  • Sender Reputation: DMARC issues can negatively impact sender reputation, making it more difficult to deliver future emails.
  • Provider Compliance: Mailbox providers actively enforce DMARC policies, making compliance essential for successful email delivery.
  • Authentication Protocols: Understanding DMARC, SPF, and DKIM is critical for effective email authentication strategies.
Marketer view

Email marketer from Stackoverflow mentions that a DMARC record that's not setup correctly with Hotmail/outlook will stop most emails as DMARC is an email authentication protocol.

November 2022 - Stackoverflow
Marketer view

Email marketer from Reddit explains that when Hotmail's DMARC policy isn't properly configured (or is missing) the email is rejected by the mail provider which ruins deliverability

June 2024 - Reddit
Marketer view

Email marketer from Mailhardener Blog shares that incorrect DMARC configuration at Hotmail could lead to legitimate emails being mistakenly flagged as spam, negatively affecting sender reputation and deliverability.

February 2025 - Mailhardener Blog
Marketer view

Email marketer from Email Geeks notes that some mailbox providers, such as Apple iCloud, are rejecting messages based on Hotmail's DMARC entries. Provides the rejection reason and a link to Apple's support page.

February 2023 - Email Geeks
Marketer view

Email marketer from Email Geeks mentions that at least iCloud and Yahoo/Verizon are rejecting messages based on Hotmail's DMARC policy.

July 2024 - Email Geeks
Marketer view

Email marketer from Email on Acid's blog responds that misconfigured or missing DMARC records related to Hotmail can lead to email delivery failures, as receiving mail servers may not trust emails claiming to be from that domain.

July 2021 - Email on Acid Blog

What the experts say
5Expert opinions

Initially, Hotmail had an issue where they were not publishing a DMARC policy correctly. This meant that emails failing DMARC checks wouldn't be identified as spoofed and could potentially harm deliverability. Later, the record was updated to 'p=none', and eventually, the DMARC record issue appears to have been fixed. The issue with the DMARC record could lead to messages being rejected and emails being seen as spoofed, negatively impacting email deliverability. A correctly configured DMARC record is important as failing DMARC checks may lead to email rejection.

Key opinions

  • Initial DMARC Issue: Hotmail initially had a problem with not publishing a DMARC policy correctly.
  • Spoofing Risk: Without a DMARC record, emails failing authentication are not identified as spoofing.
  • Record Update: The DMARC record was updated to 'p=none' during the issue.
  • Resolution: The Hotmail DMARC record issue was resolved.
  • Impact on Deliverability: DMARC issues can cause messages failing checks to be rejected, impacting deliverability.

Key considerations

  • Importance of DMARC: Correct DMARC configuration is crucial for preventing email spoofing and maintaining deliverability.
  • Email Rejection: Messages failing DMARC checks may be rejected by receiving servers.
  • Ongoing Monitoring: It is important to monitor DMARC records to ensure proper configuration.
Expert view

Expert from Email Geeks clarifies that without a DMARC record, emails will not be identified as spoofing.

January 2024 - Email Geeks
Expert view

Expert from Email Geeks checks the DMARC record and notes it seems to be returning just one record now, the p=none.

March 2022 - Email Geeks
Expert view

Expert from Word to the Wise explains that DMARC issues with Hotmail could cause messages failing DMARC checks to be rejected, severely impacting deliverability, as receivers might see these emails as spoofed.

August 2024 - Word to the Wise
Expert view

Expert from Email Geeks shares the DMARC record for _dmarc.hotmail.com, indicating an initial issue with Hotmail not publishing a DMARC policy correctly.

February 2025 - Email Geeks
Expert view

Expert from Email Geeks confirms that the Hotmail DMARC record issue appears to be fixed.

August 2024 - Email Geeks

What the documentation says
3Technical articles

According to Microsoft, DMARC.org, and Google, incorrect or missing DMARC records at Hotmail/Outlook.com can cause significant email deliverability issues. DMARC is designed to prevent email spoofing, and when issues arise with its configuration, messages may fail authentication checks. This can result in emails being rejected, marked as spam, or sent to the junk folder, thereby disrupting email delivery. The enforcement of the DMARC policy is crucial to protecting senders and recipients from spam and phishing.

Key findings

  • Deliverability Issues: Incorrect or missing DMARC records lead to email deliverability problems.
  • Spam/Rejection: Messages may be rejected or marked as spam due to DMARC issues.
  • Spoofing Prevention: DMARC is designed to prevent email spoofing.
  • Authentication Failure: Issues with DMARC records can cause messages to fail authentication checks.

Key considerations

  • Correct Configuration: It is essential to ensure DMARC records are correctly configured.
  • Policy Enforcement: Proper enforcement of the DMARC policy is crucial.
  • Protection Against Threats: DMARC helps protect against spam and phishing attacks.
  • Integration with SPF/DKIM: DMARC works in conjunction with SPF and DKIM for comprehensive email authentication.
Technical article

Documentation from Google explains that DMARC helps protect senders and recipients from spam and phishing, by letting domain owners specify how to handle emails that fail SPF or DKIM checks. So incorrect configuration would stop deliverability.

November 2023 - Google Workspace Admin Help
Technical article

Documentation from DMARC.org outlines that DMARC is designed to prevent email spoofing. Issues with DMARC records can lead to messages failing authentication checks, resulting in deliverability problems, including messages being blocked or sent to the junk folder.

January 2023 - DMARC.org
Technical article

Documentation from Microsoft Support explains that incorrect or missing DMARC records at Hotmail/Outlook.com can cause email deliverability issues, leading to messages being rejected or marked as spam. Specifically an issue with the enforcement of the DMARC policy can cause these issues.

June 2024 - Microsoft Support

Related resources
2Resources

Emails going to spam with Outlook / Hotmail : r/cpanel
Emails going to spam with Outlook / Hotmail : r/cpanel

Posted by u/cdwagmurphy - 8 votes and 17 comments

Reddit
Optimize Hotmail/Outlook Email Deliverability: Proven 10 Ways
Optimize Hotmail/Outlook Email Deliverability: Proven 10 Ways

Learn how to increase Hotmail or Outlook email deliverability for your emails. Microsoft email deliverability can be increased with a few steps to increase inbox reach easily in this guide.

Warmy Blog

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