How to resolve email deliverability issues to Outlook spam folder after subdomain change?

Summary

After a subdomain change, resolving email deliverability issues to Outlook's spam folder requires a multifaceted approach. A key initial step is to proactively contact Microsoft's postmaster support to request mitigation, clearly articulating the change. Simultaneously, it's critical to verify the scope of the problem by analyzing engagement metrics like clicks and image loads, and confirming direct reports from users landing in spam. Building a positive sender reputation from scratch involves warming up the new subdomain by gradually sending emails to the most engaged users first. Maintaining a clean email list by monitoring and reducing bounce rates is essential. The IP address's reputation must be assessed, considering a dedicated IP if on a shared one. Email authentication, particularly SPF, DKIM, and DMARC, must be correctly configured for the new subdomain, and tools like Google Postmaster Tools should be utilized to diagnose deliverability issues by tracking reputation and spam complaints. Content should be audited for spam triggers like excessive punctuation or 'spammy' keywords. Setting up feedback loops helps manage spam complaints, and segmenting email lists can improve engagement. Maintaining a consistent sender name and 'from' address builds trust, and analyzing email headers of messages that land in spam can reveal authentication or content-related triggers. Before sending, previewing content with tools like Mail-Tester offers a chance to identify potential spam triggers. Following industry best practices, and leveraging suppression lists to avoid sending to uninterested recipients further improve deliverability.

Key findings

  • MS Support: Contact Microsoft postmaster support proactively for mitigation.
  • Engagement Metrics: Monitor clicks, image loads, and spam reports to assess deliverability.
  • Subdomain Warm-up: Gradually increase sending volume to engaged users on the new subdomain.
  • List Hygiene: Reduce bounce rates through regular list cleaning.
  • IP Reputation: Ensure a good IP reputation; consider a dedicated IP.
  • Authentication: Correctly configure SPF, DKIM, and DMARC records.
  • Diagnostic Tools: Use Google Postmaster Tools to track reputation and spam complaints.
  • Content Audit: Review email content for spam triggers.
  • Feedback Loops: Set up feedback loops to manage spam complaints.
  • List Segmentation: Segment email lists to improve engagement.
  • Sender Consistency: Maintain consistent sender information.
  • Header Analysis: Analyze spam email headers for clues.
  • Content Preview: Preview emails with tools like Mail-Tester.
  • Suppression Lists: Utilize suppression lists to avoid sending to uninterested recipients.

Key considerations

  • Proactive Communication: Early communication with Microsoft support is essential.
  • Data-Driven Decisions: Use engagement and spam report data to guide decisions.
  • Reputation Building: Warming up the new subdomain is a gradual process.
  • Technical Correctness: Accurate email authentication is paramount.
  • Continuous Monitoring: Regular monitoring of key metrics is necessary.
  • Best Practices: Adherence to industry best practices is a must.

What email marketers say
9Marketer opinions

After a subdomain change, email deliverability issues to Outlook spam folders often arise due to reputation and authentication problems. Warming up the new subdomain gradually with engaged users, monitoring bounce rates, and ensuring a good IP reputation are crucial. Content analysis for spam triggers, setting up feedback loops, and segmenting email lists enhance deliverability. Maintaining consistent sender information, analyzing email headers when spam occurs, and previewing content with tools like Mail-Tester aid in identifying and resolving issues.

Key opinions

  • Warming Up: Gradually increase sending volume to the new subdomain, starting with highly engaged users to establish a positive reputation.
  • Bounce Rates: Monitor and maintain low bounce rates by regularly cleaning the email list of invalid or inactive addresses.
  • IP Reputation: Ensure the IP address associated with the new subdomain has a good reputation, considering a dedicated IP for more control.
  • Content Analysis: Review email content for spammy keywords, excessive punctuation, and poor text-to-image ratio.
  • Feedback Loops: Set up feedback loops with ISPs like Outlook to receive spam complaints and remove problematic subscribers.
  • List Segmentation: Segment email lists for targeted sending, increasing relevance and reducing spam reports.
  • Sender Consistency: Maintain a consistent sender name and 'from' address to build trust with recipients and email providers.
  • Header Analysis: Analyze email headers when emails go to spam to identify specific authentication failures or spam filter triggers.
  • Content Preview: Preview email content with tools like Mail-Tester to assess spam scores and identify potential issues.

Key considerations

  • Reputation: A new subdomain lacks established reputation, leading to initial deliverability challenges.
  • Authentication: Ensure SPF, DKIM, and DMARC are properly configured for the new subdomain.
  • Engagement: Low engagement rates can signal to ISPs that your mail is unwanted, impacting deliverability to the inbox.
  • Shared IPs: On shared IPs, your IP reputation can be affected by other senders' practices.
  • Content Triggers: Certain words, phrases, and formatting choices can trigger spam filters.
Marketer view

Email marketer from MailerCheck explains analyze email headers. When emails land in the spam folder, analyzing the email headers can provide insights into why. Look for specific clues about authentication failures or spam filter triggers.

July 2023 - MailerCheck
Marketer view

Email marketer from ZeroBounce says preview email content. Tools like Mail-Tester are useful for previewing your email's content and the email headers before sending them. It will then provide you with a spam score.

January 2022 - ZeroBounce

What the experts say
4Expert opinions

Resolving email deliverability issues to Outlook after a subdomain change involves several key actions. Opening a support ticket with Microsoft's postmaster support to request mitigation for the new subdomain is crucial, requiring clear and concise communication. Verifying deliverability problems by checking for recipient engagement (clicks, image loads) and confirming spam reports is also essential. Prioritizing sending to engaged subscribers initially helps maintain a positive sending reputation. Finally, ensure proper email authentication by verifying SPF, DKIM, and DMARC records for the new subdomain to avoid authentication failures.

Key opinions

  • MS Support Ticket: Open a support ticket with Microsoft's postmaster support for preemptive mitigation.
  • Engagement Verification: Check for clicks and image loads from Outlook recipients to verify deliverability issues.
  • Engaged Subscribers: Focus on sending to engaged subscribers first to maintain a good reputation.
  • Authentication Check: Verify SPF, DKIM, and DMARC records for the new subdomain.

Key considerations

  • Mitigation Request: Be persistent and clear when requesting mitigation from Microsoft's support team.
  • Deliverability Verification: Confirm reports of spam and check for engagement to accurately assess the problem.
  • Engagement Impact: Low engagement can negatively affect deliverability; prioritize active users.
  • Authentication Importance: Incorrect authentication records can severely impact email delivery to Outlook.
Expert view

Expert from Spam Resource responds that authentication issues need to be checked with the new sub domain. Make sure your SPF, DKIM, and DMARC records are set up correctly for the new subdomain. Incorrect or missing authentication records are a common cause of deliverability problems after a subdomain change.

April 2022 - Spam Resource
Expert view

Expert from Email Geeks suggests determining if there are any clicks or image loads from recipients at Outlook domains and confirming who is reporting the emails are going to spam to verify deliverability problems.

October 2021 - Email Geeks

What the documentation says
5Technical articles

Resolving email deliverability issues in Outlook after a subdomain change hinges on several technical factors. Maintaining a good sender reputation is paramount, which can be monitored using Microsoft's SNDS and JMRP. Ensuring correct setup of email authentication protocols (SPF, DKIM, DMARC) is critical. Google Postmaster Tools aids in diagnosing issues by tracking reputation, spam rates, and feedback loops. Utilizing suppression lists to avoid sending to unsubscribed or problematic recipients is also essential. Adhering to industry best practices, such as those outlined by M3AAWG, provides a solid foundation for outbound email.

Key findings

  • Sender Reputation: Sender reputation is critical for Outlook delivery; new subdomains lack an established reputation.
  • Email Authentication: Proper SPF, DKIM, and DMARC setup are essential for verifying email legitimacy.
  • Diagnostic Tools: Google Postmaster Tools can help diagnose deliverability issues by monitoring key metrics.
  • Suppression Lists: Using suppression lists avoids sending emails to unsubscribed or problematic recipients.
  • Industry Best Practices: Adhering to industry best practices for outbound email is crucial.

Key considerations

  • Reputation Monitoring: Regularly monitor sender reputation using tools like Microsoft's SNDS and JMRP.
  • Authentication Accuracy: Verify the accuracy of SPF, DKIM, and DMARC records to avoid authentication failures.
  • Proactive Diagnosis: Use Google Postmaster Tools proactively to identify and address potential deliverability problems.
  • List Hygiene: Maintain an up-to-date suppression list to improve sender reputation and avoid spam complaints.
  • Compliance: Stay informed about and comply with industry best practices for email sending.
Technical article

Documentation from M3AAWG shares to review and adhere to industry best practices for outbound email. Their sender best common practices are a great place to start.

March 2022 - M3AAWG
Technical article

Documentation from SparkPost recommends leveraging suppression lists. Add unsubscribed users, bounced addresses, and spam complainants to your suppression list to avoid sending them future emails. This prevents further deliverability issues and improves your sender reputation.

November 2024 - SparkPost