Why are my emails landing in the spam folder for Outlook and Hotmail?

Summary

Emails land in Outlook and Hotmail spam folders due to a complex interplay of factors, primarily related to sender reputation, email authentication, content quality and user engagement. Microsoft heavily weighs user interaction and feedback when filtering emails. Maintaining a positive sender reputation involves ensuring proper email authentication (SPF, DKIM, DMARC), monitoring IP and domain reputation through Microsoft's SNDS, and keeping complaint rates low via JMRP. Content should be clean, valuable, and avoid spam trigger words or excessive links. Permission-based marketing, consistent engagement, and regular list cleaning are crucial for improving inbox placement. Technical aspects like email headers, consistent sending IPs, and responsive email design also play a significant role. User settings in Outlook can affect whether emails are marked as spam.

Key findings

  • Authentication: Properly configured SPF, DKIM, and DMARC are essential for email authentication and improving sender reputation.
  • Sender Reputation: Sender reputation, based on IP and domain, is a major factor influencing spam placement.
  • User Engagement: Microsoft heavily weighs user engagement, with low engagement leading to spam placement.
  • Complaint Rates: High complaint rates, monitored through JMRP, negatively impact sender reputation.
  • Content Quality: Clean, valuable content, free from spam triggers and excessive links, improves deliverability.
  • List Hygiene: Regularly cleaning your email list to remove unengaged subscribers and spam traps is crucial.
  • User Feedback: Microsoft relies heavily on user feedback; encouraging subscribers to mark emails as 'not spam' can help.

Key considerations

  • Technical Setup: Analyze email headers to ensure full alignment with SPF, DKIM, DMARC, and the Return-Path.
  • Permission: Use permission-based marketing, obtaining explicit consent from subscribers.
  • IP Warm-up: Gradually warm up new IPs to avoid triggering spam filters when sending large volumes.
  • SNDS/JMRP: Monitor SNDS to check IP/domain reputation and JMRP to track complaint rates.
  • Content Sensitivity: Be mindful of content sensitivity in Hotmail/Outlook, avoiding spam trigger words.
  • Design: Ensure responsive email designs with text versions for proper rendering across devices.
  • Complaint Handling: Actively monitor and address complaints, unsubscribing users who report spam.
  • List Segmentation: Segment your audience and personalize email content to boost engagement.
  • Consistent IPs: Use consistent sending IPs or dedicated IPs for high volume sends.
  • User Settings: Be aware that Outlook user settings can impact spam filtering.
  • Patience: Building a positive sender reputation requires time and consistent effort.
  • Volume: Reducing sending volume to engaged users can help repair reputation problems.

What email marketers say
11Marketer opinions

Emails land in Outlook and Hotmail spam folders due to a combination of factors, primarily related to sender reputation, email authentication, content quality, and user engagement. Maintaining a positive sender reputation involves ensuring proper email authentication (SPF, DKIM, DMARC), monitoring IP and domain reputation through Microsoft's SNDS, and keeping complaint rates low via JMRP. Content should be clean, valuable, and avoid spam trigger words or excessive links. Permission-based marketing, consistent engagement, and regular list cleaning are crucial for improving inbox placement. User feedback plays a significant role, and encouraging subscribers to mark emails as 'not spam' can help.

Key opinions

  • Authentication: Properly configure SPF, DKIM, and DMARC records to authenticate your emails and improve sender reputation.
  • Sender Reputation: Monitor your IP and domain reputation using Microsoft's SNDS to identify and address any issues impacting deliverability.
  • User Engagement: Low engagement, high bounce rates, and high complaint rates are significant factors contributing to spam placement.
  • Content Quality: Avoid spam trigger words, excessive links, and large images. Focus on delivering clean, valuable, and personalized content.
  • List Hygiene: Regularly clean your email list to remove unengaged subscribers and spam traps.
  • User Feedback: Encourage subscribers to mark emails as 'not spam' to improve your sender reputation with Microsoft.

Key considerations

  • Email Headers: Analyze email headers to ensure full alignment with SPF, DKIM, DMARC, and the Return-Path.
  • Permission-Based Marketing: Only send emails to subscribers who have explicitly given their consent to receive them.
  • Warming Up IPs: Gradually warm up new IPs before sending large volumes of emails to avoid triggering spam filters.
  • Microsoft SNDS/JMRP: Utilize Microsoft SNDS to check IP and domain reputation and use their JMRP program to monitor complaint rates.
  • Email Design: Ensure your email designs are responsive, render correctly across devices, and include text versions.
  • Content Sensitivity: Be aware that Hotmail/Outlook is sensitive to content. Avoid spam trigger words and focus on valuable information.
  • Feedback Loops: Implement feedback loops to receive and process complaints efficiently.
  • Patience: Building a positive sender reputation with Microsoft takes time and consistent effort.
Marketer view

Email marketer from Neil Patel shares that cleaning your email list, segmenting your audience, and personalizing email content can help boost engagement and sender reputation, thus avoiding the spam folder. Also recommends using a dedicated IP address and monitoring your sender score.

December 2024 - Neil Patel
Marketer view

Email marketer from Gmass advises that Microsoft uses algorithms, user behavior and feedback to determine if messages are spam, and says if many mark as junk that this will cause spam problems. They also advise using the Microsoft SNDS to check your IP and domain reputation and to use their JMRP program to monitor complaint rates. Finally they advise that you should be patient and build up your reputation over time.

February 2023 - Gmass
Marketer view

Email marketer from Mailchimp explains the importance of permission-based marketing. Getting explicit consent from subscribers and avoiding purchased lists are key to maintaining a healthy sender reputation and improving inbox placement. Consistent engagement and relevant content are also vital.

March 2023 - Mailchimp
Marketer view

Email marketer from Sendinblue shares the importance of monitoring bounce rates and complaint rates. High bounce and complaint rates signal poor list hygiene and can significantly damage sender reputation, leading to spam placement. Regular list cleaning is recommended.

January 2022 - Sendinblue
Marketer view

Email marketer from Reddit user suggests checking if your domain or IP is blacklisted. He also emphasizes warming up new IPs gradually before sending large volumes of emails to avoid triggering spam filters.

March 2022 - Reddit
Marketer view

Email marketer from Email Geeks advises checking Microsoft's SNDS for IP reputation, as sender reputation and recipient engagement are key factors in spam placement.

September 2024 - Email Geeks
Marketer view

Email marketer from Stack Overflow user responds, saying that Hotmail is very sensitive to email content. Avoid using spam trigger words, excessive links, or large images. Focus on creating clean and valuable content for your subscribers.

October 2024 - Stack Overflow
Marketer view

Email marketer from EmailGeeks Forum shares that Microsoft relies heavily on user feedback. Encourage your subscribers to mark your emails as 'not spam' if they end up in the junk folder to improve your sender reputation.

January 2025 - EmailGeeks Forum
Marketer view

Email marketer from Email Geeks suggests analyzing email headers to ensure full alignment with SPF, DKIM, DMARC, and the Return-Path, to troubleshoot email deliverability issues in Outlook.

April 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks asks if the Outlook issue refers to O365 or Outlook Consumer (Hotmail) and provides a form link for O365 senders to fill out.

May 2022 - Email Geeks
Marketer view

Email marketer from Litmus stresses the importance of email design, and making sure it's responsive and renders correctly across various devices and email clients, especially on mobile. Also ensure you have text versions available as spam filters can flag emails without these.

January 2022 - Litmus

What the experts say
3Expert opinions

Emails land in Outlook and Hotmail spam folders due to a strong emphasis on user engagement and feedback by Microsoft's internal reputation service. Low engagement metrics, as highlighted by SpamResource, directly impact deliverability. High complaint rates, tracked via Microsoft's JMRP (explained by Word to the Wise), also lead to spam placement. Key strategies to improve inboxing include focusing on engaged users, cleaning email lists, ensuring valuable content, and actively monitoring and addressing complaint rates.

Key opinions

  • User Engagement: Microsoft heavily relies on user reactions (engagement) to filter emails. Low engagement leads to spam placement.
  • Complaint Rates: High complaint rates, as monitored through JMRP, negatively impact sender reputation and increase the likelihood of spam filtering.
  • Content Value: Providing valuable content that users want to engage with is crucial for avoiding the spam folder.
  • Internal Reputation: Microsoft uses their own internal reputation service in addition to public metrics, meaning it's important to focus on what the end user see's.

Key considerations

  • List Cleaning: Regularly clean your email list to remove unengaged subscribers and improve engagement metrics.
  • Targeted Sending: Focus your sending efforts on users who are actively engaged with your emails.
  • JMRP Monitoring: Actively monitor JMRP data to identify and address the root causes of complaints.
  • Complaint Resolution: Close the loop on complaints by unsubscribing users who report your emails as spam.
  • Reduced Sending Volume: Consider temporarily reducing sending volume and focusing only on engaged users to repair reputation.
Expert view

Expert from SpamResource explains that persistent deliverability issues with Hotmail/Outlook often stem from low engagement metrics. They emphasize that Microsoft heavily weighs user interaction (or lack thereof) when filtering. They suggest cleaning your list, targeting engaged users, and ensuring your content is valuable to avoid the spam folder.

March 2022 - SpamResource
Expert view

Expert from Email Geeks shares insights on Microsoft's internal reputation service, which is based on user reactions. Also explains SCL ratings and Return Path Certification. Also explains SNDS is content based. Suggests reducing sending volume and focusing on engaged users to improve reputation.

June 2024 - Email Geeks
Expert view

Expert from Word to the Wise explains that Microsoft's JMRP program allows senders to monitor complaint rates. High complaint rates can significantly impact your sender reputation and lead to spam placement. They advise regularly reviewing JMRP data and addressing the root causes of complaints. Also advise closing the loop on complaints by unsubscribing users when they complain.

January 2025 - Word to the Wise

What the documentation says
4Technical articles

Emails land in Outlook and Hotmail spam folders due to a confluence of factors, including sender reputation, email content, user settings within Outlook, and technical configuration issues. Key to avoiding spam filters is maintaining a good sender reputation through proper email authentication (SPF, DKIM, DMARC), consistently monitoring sender reputation services (SNDS), using consistent sending IPs, ensuring a low spam complaint rate, and providing an easy unsubscribe process. High volume senders should also consider dedicated IP addresses and actively manage their subscriber lists to remove spam traps.

Key findings

  • Sender Reputation: Maintaining a good sender reputation is critical for avoiding spam filters.
  • Email Authentication: Implementing SPF, DKIM, and DMARC is essential for authenticating emails.
  • SNDS Monitoring: Consistently monitoring SNDS helps identify and address issues impacting reputation.
  • Spam Complaint Rate: Maintaining a low spam complaint rate is crucial for deliverability.
  • Unsubscribe Process: Providing an easy unsubscribe process helps reduce spam complaints.

Key considerations

  • User Settings: Be aware that user settings in Outlook can affect whether emails are marked as spam.
  • Consistent IPs: Use consistent sending IPs to build a positive reputation.
  • Dedicated IPs: High volume senders should consider using dedicated IP addresses.
  • Spam Trap Removal: Proactively identify and remove spam traps from your subscriber list.
Technical article

Documentation from Google Workspace advises senders to ensure accurate configuration of SPF, DKIM, and DMARC records. Additionally, it highlights the significance of consistent sending IPs, maintaining a low spam complaint rate, and providing an easy unsubscribe process to prevent emails from landing in the spam folder.

July 2021 - Google Workspace
Technical article

Documentation from Microsoft Support explains that Outlook's spam filter automatically evaluates messages, and several factors can cause emails to be marked as spam, including sender reputation, content, and user settings. Users can adjust their filter settings to allow specific senders.

July 2023 - Microsoft Support
Technical article

Documentation from SparkPost highlights the significance of consistently authenticating your sending domain using SPF, DKIM and DMARC. They also emphasize the need for dedicated IP addresses for sending high email volumes, and proactively identifying and removing spam traps from your subscriber list.

April 2024 - SparkPost
Technical article

Documentation from Outlook Postmaster emphasizes the importance of maintaining a good sender reputation. They recommend implementing SPF, DKIM, and DMARC for email authentication. Also, consistently monitoring SNDS (Smart Network Data Services) to address any issues impacting reputation.

September 2022 - Outlook Postmaster