How to troubleshoot email deliverability issues with Microsoft domains?

Summary

Troubleshooting email deliverability with Microsoft domains requires a holistic approach encompassing sender reputation, list hygiene, authentication, content, and engagement. Maintaining a positive sender reputation is paramount, involving monitoring IP and domain reputation using tools like Sender Score, Talos, Microsoft's SNDS, and JMRP. Diligent list management is crucial, requiring regular removal of invalid addresses, hard bounces, and unsubscribes. Proper email authentication (SPF, DKIM, DMARC) is essential to verify sender identity and prevent spoofing. Email content should avoid spam triggers, excessive images, and broken HTML. Monitoring deliverability metrics like bounce rates, complaint rates, and placement rates aids in proactive problem identification. Strategies also involve reducing active sending segments to improve reputation, investigating bounce reasons, and considering dedicated IPs for high-volume senders. Utilizing Microsoft's Sender Support portal assists in troubleshooting and delisting blocked IPs, and adhering to SMTP standards is essential.

Key findings

  • Sender Reputation: Maintaining a good sender reputation with Microsoft is crucial; monitor your IP and domain reputation using tools like Sender Score, Talos, SNDS, and JMRP.
  • List Hygiene: Clean list management is essential. Regularly remove invalid email addresses, hard bounces, and unsubscribes.
  • Email Authentication: Proper email authentication (SPF, DKIM, DMARC) is essential for verifying sender identity and preventing spoofing.
  • Content: Avoid spam trigger words, excessive use of images, and broken HTML in your email content.
  • Engagement: Low engagement metrics (low open/click rates) negatively impact reputation; focus on sending to engaged users.
  • Monitoring: Monitor deliverability metrics like bounce rates, complaint rates, and placement rates to proactively identify issues.
  • Complex Filtering: Microsoft uses a complex filtering system considering sender reputation, content, and user engagement.
  • SMTP standards: It's important to ensure that your email infrastructure adheres to SMTP standards

Key considerations

  • Reduce Active Segment: If experiencing issues, reduce the active sending segment until reputation improves, then slowly expand.
  • Investigate Bounces: Examine bounce reasons for patterns indicating list acquisition or bot issues.
  • Alternative Communication: Attempt communication via different channels to diagnose delivery issues with specific domains.
  • Dedicated IP: Consider using a dedicated IP address for sending emails, especially for high-volume senders.
  • Feedback Loops: Set up feedback loops with Microsoft to receive notifications about spam complaints.
  • Throttling: Monitor sending volume to avoid being throttled by Microsoft due to poor reputation.
  • Utilize Sender Support: Use Microsoft's Sender Support portal to troubleshoot and request delisting.
  • Shared vs Dedicated IPs: Deliverability problems are more likely on Shared SES IPs than Dedicated IPs

What email marketers say
14Marketer opinions

Troubleshooting email deliverability issues with Microsoft domains involves a multi-faceted approach focusing on sender reputation, list hygiene, authentication, content, and engagement. Maintaining a positive sender reputation with Microsoft is paramount, involving monitoring IP and domain reputation through tools like Sender Score and Microsoft's SNDS/JMRP. Clean list management is crucial, requiring regular removal of inactive addresses, hard bounces, and unsubscribes. Proper email authentication (SPF, DKIM, DMARC) is essential to verify sender identity and prevent spoofing. Email content should avoid spam triggers, excessive images, and broken HTML, with testing recommended. Monitoring deliverability metrics like bounce rates and complaint rates aids in proactive problem identification. Strategies also involve reducing active sending segments to improve reputation, investigating bounce reasons, and considering dedicated IPs for high-volume senders.

Key opinions

  • Sender Reputation: Maintaining a good sender reputation with Microsoft is crucial. Monitor your IP and domain reputation using tools like Sender Score, Talos and Microsoft's SNDS/JMRP.
  • List Hygiene: Clean list management is essential. Regularly remove invalid email addresses, hard bounces, and unsubscribes to improve sender reputation.
  • Email Authentication: Proper email authentication (SPF, DKIM, DMARC) is essential to verify sender identity and prevent spoofing.
  • Content: Avoid spam trigger words, excessive use of images, and broken HTML in your email content. Test your content with spam filters before sending.
  • Engagement: Low engagement metrics (low open/click rates) negatively impact reputation. Focus on sending to engaged users.
  • Monitoring: Monitor deliverability metrics like bounce rates, complaint rates, and placement rates to proactively identify issues.

Key considerations

  • Reduce Active Segment: If experiencing issues, reduce the active sending segment until reputation improves, then slowly expand.
  • Investigate Bounces: Examine bounce reasons for patterns indicating list acquisition or bot issues.
  • Alternative Communication: Attempt communication via different channels to diagnose delivery issues with specific domains.
  • Dedicated IP: Consider using a dedicated IP address for sending emails, especially for high volume senders.
  • Feedback Loops: Set up feedback loops with Microsoft to receive notifications about spam complaints.
  • Throttling: Monitor sending volume to avoid being throttled by Microsoft due to poor reputation.
  • Shared vs Dedicated IPs: Deliverability problems are more likely on Shared SES IPs than Dedicated IPs
Marketer view

Marketer from Email Geeks shares they have also experienced MSN problems and suggests reducing frequency and tightening engagement filters. Also they found that there was only an issue when using SES IPs (shared pool) but not when using dedicated IPs.

October 2023 - Email Geeks
Marketer view

Email marketer from Email Marketing Forum says consider using a dedicated IP address for sending emails, especially if you send a high volume of emails. A dedicated IP allows you to build your own reputation, which can improve deliverability.

May 2023 - Email Marketing Forum
Marketer view

Email marketer from Quora explains setting up feedback loops with Microsoft allows you to receive notifications when recipients mark your emails as spam. This information can help you identify and address issues that are causing your emails to be flagged as spam.

November 2023 - Quora
Marketer view

Email marketer from SendGrid explains that Microsoft may throttle emails from senders with poor reputations. Monitor your sending volume and adjust if necessary to avoid being throttled.

February 2023 - SendGrid
Marketer view

Email marketer from Mailjet shares it's crucial to maintain a clean email list by removing inactive subscribers, hard bounces, and unsubscribes. Regularly cleaning your list helps improve your sender reputation.

October 2022 - Mailjet
Marketer view

Email marketer from Litmus recommends to avoid spam trigger words, excessive use of images, and broken HTML in your email content. Test your email content with spam filters before sending.

July 2022 - Litmus
Marketer view

Email marketer from EmailOnAcid suggests checking your sending IP address against common blocklists. If your IP is listed, work to get it removed according to the blocklist's procedures.

September 2021 - EmailOnAcid
Marketer view

Marketer from Email Geeks advises grabbing a sample of the addresses with the same bounce reason and retracing their steps (signup source, engagement, etc.) to identify commonalities like potential bot abuse or issues with lead gen companies. They note the bounce reason is specific to the address, not sender reputation, but sending to many such addresses could impact deliverability.

January 2025 - Email Geeks
Marketer view

Marketer from Email Geeks suggests determining if you can communicate with the affected domains via a different channel to debug the problem. If it's all opt-in, email them from your work account and ask them to confirm reception.

April 2021 - Email Geeks
Marketer view

Email marketer from Reddit shares the importance of engagement metrics. Low engagement, such as low open rates and click-through rates, can negatively impact your reputation with Microsoft and lead to deliverability issues. Focus on sending emails to engaged users.

July 2022 - Reddit
Marketer view

Email marketer from MailerQ shares that it's crucial to monitor your email deliverability metrics, such as bounce rates, complaint rates, and placement rates. Use these metrics to identify and address deliverability issues proactively.

October 2022 - MailerQ
Marketer view

Email marketer from StackOverflow emphasizes the importance of proper email authentication (SPF, DKIM, DMARC) to improve deliverability with Microsoft. Ensure that your domain is properly configured to authenticate your emails.

May 2021 - StackOverflow
Marketer view

Marketer from Email Geeks shares that in their experience with Microsoft deliverability issues, the solution has always been to reduce the active segment until the reputation improves, then slowly expand it. They suggest focusing on actives from the last 15 days.

July 2021 - Email Geeks
Marketer view

Email marketer from Microsoft Support recommends using sender reputation services like Sender Score or Talos to check your sending IP's reputation with Microsoft. A poor reputation can cause deliverability problems.

July 2023 - Microsoft Support

What the experts say
4Expert opinions

Troubleshooting email deliverability issues with Microsoft domains requires a focus on sender reputation, list hygiene, and email authentication. Maintaining a good sender reputation is crucial, involving monitoring your IP and domain using Microsoft's SNDS and JMRP. Diligent list management, including removing invalid addresses and processing bounce messages, is vital as Microsoft considers it a key factor in sender reputation. Implementing proper email authentication mechanisms like SPF, DKIM, and DMARC is also essential to improve deliverability and prevent spoofing.

Key opinions

  • Sender Reputation: Maintaining a good sender reputation is essential for deliverability with Microsoft. Monitor using SNDS and JMRP.
  • List Hygiene: Diligent list management, including removing invalid addresses and processing bounces, improves reputation.
  • Email Authentication: Implementing SPF, DKIM, and DMARC is crucial for improving deliverability and preventing spoofing.
  • Complex Filtering: Microsoft uses complex filtering considering sender reputation, content, and user engagement.

Key considerations

Expert view

Expert from Word to the Wise explains the importance of maintaining a good sender reputation when sending to Microsoft domains. Monitor your IP and domain reputation using Microsoft's SNDS and JMRP, and take steps to address any issues that arise. Poor reputation is a primary cause of deliverability issues with Microsoft.

January 2023 - Word to the Wise
Expert view

Expert from Spam Resource advises practicing diligent list management, including regularly removing invalid email addresses and promptly processing bounce messages. Microsoft considers list hygiene a critical factor in determining sender reputation.

February 2025 - Spam Resource
Expert view

Expert from Word to the Wise, explains that Microsoft uses a complex filtering system that considers various factors, including sender reputation, content, and user engagement. Understanding these factors and optimizing your email program accordingly is crucial for improving deliverability.

February 2025 - Word to the Wise
Expert view

Expert from Spam Resource emphasizes the importance of implementing proper email authentication mechanisms, such as SPF, DKIM, and DMARC, to improve deliverability with Microsoft. Ensure that your domain is properly configured to authenticate your emails and prevent spoofing.

April 2021 - Spam Resource

What the documentation says
4Technical articles

Troubleshooting email deliverability issues with Microsoft domains involves addressing IP reputation, content, authentication, and list hygiene. Utilizing Microsoft's Sender Support portal aids in troubleshooting and delisting blocked IPs. Enrolling in the Junk Email Reporting Program (JMRP) provides feedback on emails marked as junk, helping identify problems. Adhering to SMTP standards, including HELO/EHLO configuration and proper bounce handling, is also crucial.

Key findings

  • Common Issues: Common deliverability issues are related to IP reputation, content, authentication, and list hygiene.
  • JMRP: Enrolling in the Junk Email Reporting Program (JMRP) provides feedback on emails marked as junk.
  • Sender Support Portal: The Sender Support portal helps troubleshoot delivery issues and request delisting of blocked IPs.
  • SMTP Standards: Adhering to SMTP standards is crucial for deliverability.

Key considerations

Technical article

Documentation from Microsoft advises to use the Sender Support portal to troubleshoot delivery issues and request delisting if your IP address has been blocked.

May 2024 - Microsoft
Technical article

Documentation from Microsoft recommends enrolling in the JMRP. This program provides feedback on when your emails are marked as junk by recipients, allowing you to identify and address potential problems.

February 2022 - Microsoft
Technical article

Documentation from RFC explains ensuring your email infrastructure adheres to SMTP standards, including correct HELO/EHLO configuration and proper handling of bounce messages, is crucial for deliverability.

July 2024 - RFC
Technical article

Documentation from Microsoft explains that common issues are related to IP reputation, content, authentication, and list hygiene. It recommends reviewing these areas to identify the cause of deliverability problems.

November 2024 - Microsoft