How to resolve email blocking issues with Microsoft domains?

Summary

Resolving email blocking issues with Microsoft domains requires a holistic approach, addressing both technical and strategic aspects of email sending. It begins with ensuring your IP is not on blocklists and proper email authentication via SPF, DKIM, and DMARC. Monitoring your sender reputation through Microsoft's SNDS is crucial, as is actively managing subscriber lists and ensuring explicit consent. Experts recommend looking beyond Microsoft-specific solutions and addressing underlying issues with acquisition and mailing practices. Creating engaging content, managing bounces and complaints, and warming up IP addresses also contribute to improved deliverability. For B2C mail, temporarily suspending sending to 'obvious' Microsoft domains can provide relief, while O365 mail may require filtering by MX IP range. Engaging directly with Microsoft with details of your practices is beneficial. Participating in feedback loops like JMRP is also recommended, as are content and code audits to prevent triggering spam filters.

Key findings

  • Authentication is Critical: Properly configured SPF, DKIM, and DMARC records are essential for establishing trust and improving deliverability.
  • Reputation Management: Regularly monitoring sender reputation through SNDS and other tools helps identify and address issues proactively.
  • List Hygiene: Maintaining a clean and engaged subscriber list is crucial for avoiding spam complaints and improving sender reputation.
  • Address Root Causes: Blocking issues are often symptoms of underlying problems in acquisition or mailing practices that need to be fixed.
  • Engagement is key: Engaging content and positive recipient interactions are vital for maintaining a good sender reputation with Microsoft.

Key considerations

  • Technical Setup: Ensure correct configuration and validation of SPF, DKIM, and DMARC records.
  • Continuous Monitoring: Regularly monitor IP and domain reputation using SNDS and other tools to identify potential issues.
  • Data Collection: Participating in feedback loops and reviewing complaints, JMRP, and bounces provides invaluable data for improving practices.
  • Compliance: Ensure that data privacy laws are followed.
  • Adaptation: Understand Microsoft's filtering policies and adapting accordingly will help maintain strong deliverability.

What email marketers say
8Marketer opinions

Resolving email blocking issues with Microsoft domains involves a multi-faceted approach. Key strategies include maintaining a clean and engaged email list, segmenting your audience, and using a reputable Email Service Provider (ESP). Equally important is adhering to email authentication best practices (SPF, DKIM, DMARC) and consistently monitoring your sender reputation through tools like Microsoft's SNDS. Analyzing bounce codes and avoiding spam triggers in your content are crucial for troubleshooting. Engaging with Microsoft's support channels and feedback loops (JMRP) can also aid in identifying and rectifying specific issues.

Key opinions

  • Clean List: Building and maintaining a clean email list is fundamental for avoiding blocks.
  • Authentication: Properly configuring SPF, DKIM, and DMARC records is essential for email authentication.
  • Reputation Monitoring: Regularly monitoring your sender reputation is crucial for identifying and addressing issues proactively.
  • Content Analysis: Reviewing email content for spam triggers helps prevent deliverability problems.
  • Engagement Matters: Engagement with emails and keeping your audience engaged is key to deliverability

Key considerations

  • Proactive Monitoring: Continuously monitor your sender reputation and deliverability metrics to detect issues early.
  • Authentication Setup: Ensure your SPF, DKIM, and DMARC records are correctly configured and validated.
  • Content Optimization: Optimize your email content to avoid spam triggers and provide value to recipients.
  • List Hygiene: Regularly clean your email list to remove unengaged subscribers and reduce bounce rates.
  • Feedback Loops: Consider if you are part of feedback loops with email providers, this will provide valuable insight to any possible issues.
Marketer view

Email marketer from Neil Patel shares that improving email deliverability requires building a clean email list, segmenting your audience, using a reputable email service provider (ESP), and consistently monitoring your sender reputation.

August 2021 - Neil Patel
Marketer view

Email marketer from Email on Acid shares that troubleshooting email deliverability issues involves checking your IP reputation, analyzing bounce codes, reviewing your email content for spam triggers, and testing your email rendering across different email clients.

May 2023 - Email on Acid
Marketer view

Marketer from Email Geeks suggests that if you are being blocked by Microsoft then you have problems which need to be addressed as they will start to show up with other providers too.

May 2024 - Email Geeks
Marketer view

Email marketer from Email Marketing Forum explains that warming up your IP address, monitoring your sender reputation through Microsoft's SNDS, and actively managing your subscriber list can help in resolving email blocking issues with Microsoft domains.

October 2021 - Email Marketing Forum
Marketer view

Email marketer from Reddit suggests checking your domain and IP reputation using online tools like MXToolbox and ensuring your SPF, DKIM, and DMARC records are correctly configured to improve deliverability with Microsoft.

April 2024 - Reddit
Marketer view

Email marketer from Mailjet explains that to stay off email blocklists, ensure you have explicit consent from subscribers, regularly clean your email list, avoid sending spam-like content, and monitor your IP address reputation.

February 2022 - Mailjet
Marketer view

Email marketer from GlockApps shares that improve sender reputation monitor your IP addresses and domain reputation, and clean your email list to remove unengaged subscribers to improve your sending score.

August 2023 - GlockApps
Marketer view

Email marketer from SparkPost explains that understanding Microsoft's filtering involves adhering to their best practices, monitoring your reputation with SNDS, and engaging with Microsoft's support channels to address specific blocking issues.

October 2023 - SparkPost

What the experts say
5Expert opinions

Resolving email blocking issues with Microsoft domains often requires addressing underlying problems within your mailing practices rather than solely focusing on Microsoft. Key strategies include fixing acquisition methods, ensuring consent, managing bounces and complaints, and creating engaging content. For B2C mail, temporarily suspending sending to obvious Microsoft domains can help. For O365, filtering by recipient MX IP range or suspending upon rejection are viable options. Direct communication with Microsoft, detailing your mailing practices and subscriber acquisition methods, can lead to resolution. Participating in Microsoft's JMRP helps identify and address issues based on recipient feedback. Email authentication and sender reputation monitoring are essential.

Key opinions

  • Underlying Issues: Microsoft blocking often stems from broader problems in acquisition or mailing practices.
  • Targeted Action: Specific actions like suspending sending to certain domains or filtering MX IP ranges can provide temporary relief.
  • Direct Communication: Directly engaging with Microsoft can lead to a resolution by demonstrating responsible mailing practices.
  • Feedback is key: Leveraging services like JMRP provide key information for improvement.
  • Engagement Is Key: Engaging content and a clean subscriber lists is a must for Microsoft Deliverability.

Key considerations

  • Acquisition Practices: Review and improve your subscriber acquisition methods to ensure consent and quality.
  • Mail Stream Segmentation: Distinguish between B2C and O365 mail streams and apply appropriate mitigation techniques.
  • Microsoft Engagement: Be prepared to provide detailed information about your mailing practices when contacting Microsoft.
  • Holistic Approach: Address blocking issues by improving your mailing practices as a whole (acquisition, suppression etc).
  • Feedback Loops: Consider feedback loop program involvement to help provide data and insight to any issues.
Expert view

Expert from Email Geeks suggests that if you're getting blocked by Microsoft, the underlying problem is likely not Microsoft itself, and recommends fixing acquisition or mailing practices for a long-term solution.

December 2023 - Email Geeks
Expert view

Expert from Word to the Wise explains that, to improve deliverability with Microsoft, focus on engaging content, obtain explicit consent, manage bounces and complaints, authenticate your emails, monitor your sender reputation, and actively participate in feedback loops like JMRP.

June 2022 - Word to the Wise
Expert view

Expert from Spam Resource explains that Microsoft's JMRP allows senders to receive reports about recipients who mark their emails as junk, which helps identify and address issues leading to negative feedback and potential blocking.

July 2024 - Spam Resource
Expert view

Expert from Email Geeks says that if it's B2C mail, suspending mailing to the "obvious" Microsoft domains won't hurt too much. If it's O365, then you'll need to either filter by recipient MX IP range (easy enough to do on the MTA, a PITA to do anywhere else) or just suspend when you see each rejection.

July 2024 - Email Geeks
Expert view

Expert from Email Geeks shares an experience of directly contacting Microsoft with details about mailing practices, subscriber acquisition, and suppression methods, which led to a resolution of the blocking issue and improved email performance.

August 2024 - Email Geeks

What the documentation says
3Technical articles

Resolving email blocking issues with Microsoft domains, as outlined by official documentation, centers around ensuring proper email authentication, monitoring sender reputation, and adhering to Microsoft's guidelines. Key steps include verifying that your sending IP is not on blocklists, correctly configuring SPF, DKIM, and DMARC records, and actively monitoring your IP reputation using Microsoft's SNDS program. Effectively using SNDS involves regularly checking your reputation, investigating complaints, and following Microsoft's sending best practices. Implementing DMARC requires creating a DMARC record, monitoring DMARC reports for authentication failures, and gradually enforcing a policy to protect against spoofing.

Key findings

  • Blocklist Check: Ensuring your IP is not on any blocklists is a primary step.
  • Authentication Protocols: Correctly configured SPF, DKIM, and DMARC are crucial for authentication.
  • Reputation Monitoring: Regular monitoring of IP reputation using Microsoft's SNDS is essential.
  • DMARC Implementation: Implementing DMARC helps protect against spoofing and improves deliverability.

Key considerations

  • SNDS Utilization: Regularly monitor SNDS to identify and address any reputation issues.
  • DMARC Enforcement: Gradually increase your DMARC policy to quarantine or reject to maximize protection.
  • Proactive Reputation Management: Adhere to Microsoft's sending guidelines to maintain a positive reputation proactively.
  • Validation: Validate your Authentication is setup correctly.
Technical article

Documentation from Microsoft Support explains that to resolve email delivery issues, ensure your sending IP address is not on any blocklists, configure SPF, DKIM, and DMARC records correctly, and monitor your sender reputation using Microsoft's SNDS program.

August 2022 - Microsoft Support
Technical article

Documentation from DMARC.org explains that implementing DMARC involves creating a DMARC record in your DNS, monitoring DMARC reports to identify authentication failures, and gradually increasing your DMARC policy to quarantine or reject to protect your domain from spoofing and improve deliverability.

January 2025 - DMARC.org
Technical article

Documentation from Microsoft SNDS explains that to use SNDS effectively, regularly monitor your IP reputation, investigate and address any complaints, and adhere to Microsoft's sending guidelines to maintain a positive reputation.

June 2024 - Microsoft SNDS