Why are my emails going to the Outlook/Hotmail junk folder despite good IP reputation and how do I fix it?

Summary

Despite a good IP reputation, emails may land in Outlook/Hotmail junk folders due to domain reputation, problematic content, user interactions, and feedback loops. Monitor Microsoft's Smart Network Data Services (SNDS), ensure proper authentication (SPF, DKIM, DMARC), and send engaging content. Good list hygiene is crucial. Check for blocklisting and address issues promptly. If delivered to the bulk folder, recipients moving the email to the inbox helps. Warm up IPs focusing on engaged users. Test content and monitor if emails initially land in the inbox before moving to junk.

Key findings

  • Holistic Reputation: Deliverability depends not only on IP but also on domain reputation, content, user engagement, and feedback loops.
  • SNDS Importance: Microsoft SNDS provides specific reputation data, crucial for Outlook/Hotmail deliverability.
  • Authentication Matters: Proper authentication is essential to prove sender legitimacy.
  • Engagement Signals: High engagement rates signal positive reputation, while low engagement can harm it.
  • List Hygiene Critical: Clean email lists improve sender reputation and reduce junk folder placement.
  • Content Triggers: Spammy content (words, formatting) triggers junk filters.
  • Blocklist Impact: Listing on blocklists hurts deliverability, even with a good IP reputation.
  • User Action Effects: Users moving emails from junk to inbox improves future delivery.

Key considerations

  • Monitor SNDS: Regularly monitor SNDS to identify and address deliverability issues promptly.
  • Authenticate Email: Implement SPF, DKIM, and DMARC to authenticate your sending domain.
  • Engage Users: Focus on sending relevant and engaging content to improve open/click rates.
  • Clean Lists: Regularly remove invalid and inactive email addresses from your list.
  • Test Content: A/B test different subject lines and body content to avoid spam triggers.
  • Manage Reputation: Address blocklist listings and improve overall sender reputation through best practices.
  • Warm Up IP: Focus IP warmup on engaged users.
  • Delivery Location: Monitor if emails go straight to Junk or Inbox initially.

What email marketers say
11Marketer opinions

Despite a good IP reputation, emails may still land in Outlook/Hotmail junk folders due to various factors. These include how users interact with your emails (marking them as junk), content-related issues (spam trigger words, excessive formatting), domain reputation problems, feedback loops where negative feedback trains Outlook's filters, lack of proper authentication (SPF, DKIM, DMARC), poor list hygiene (sending to invalid addresses), and low user engagement (low open/click rates). Microsoft also considers whether emails initially land in the inbox and then move to junk. Monitoring SNDS data and addressing identified issues, warming up IP addresses correctly, and opening support tickets with Microsoft when necessary are all recommended.

Key opinions

  • User Interaction: Users marking emails as junk train Outlook's filters, affecting future deliverability.
  • Content Matters: Spam trigger words, excessive formatting (all caps, exclamation points), and subject line issues can trigger spam filters.
  • Domain Reputation: A negative domain reputation can override a good IP reputation and impact deliverability.
  • Feedback Loops: Negative feedback from recipients (marking as junk) contributes to filtering decisions.
  • Authentication: Proper authentication (SPF, DKIM, DMARC) is crucial for improving deliverability to Hotmail/Outlook.
  • List Hygiene: Sending to invalid or inactive email addresses harms sender reputation and deliverability.
  • User Engagement: Low open/click rates signal to Microsoft that your emails may not be valuable, impacting deliverability.
  • Monitoring: Continuous monitoring of your sender reputation via SNDS helps identify and resolve deliverability issues.
  • Delivery Path: It's important to know if the emails are landing in the inbox first before moving to junk. This indicates different issues than direct delivery to junk.

Key considerations

  • Email Warmup: Focus on recipients who actively engage with your emails when warming up a new IP address.
  • Content A/B Testing: A/B test different subject lines and body content to identify potential spam triggers.
  • Microsoft SNDS: Regularly check and analyze data from Microsoft's Smart Network Data Services (SNDS) to proactively manage your IP and domain reputation.
  • Relevance and Value: Focus on creating highly relevant and valuable content to improve user engagement and sender reputation.
  • Remediation Plan: Establish a plan to address deliverability issues promptly, including opening a support ticket with Microsoft if necessary.
  • Email List Cleaning: Purge any old, unengaged or invalid email addresses from your email list.
Marketer view

Email marketer from EmailGeek shares that users mark messages as junk which trains Outlook to do so. Senders need to use feedback loops, authenticate email, get added to address books, test content with Outlook, use a dedicated IP address, monitor sender reputation and follow best practices.

November 2022 - EmailGeek
Marketer view

Email marketer from Mailtrap Blog shares that a common reason for emails landing in the junk folder is the content itself. Using excessive exclamation points, all caps, or spam trigger words can negatively impact deliverability. Optimize your content for better results.

September 2021 - Mailtrap Blog
Marketer view

Email marketer from Mailjet shares that to improve deliverability to Hotmail/Outlook, ensure you're authenticated with SPF, DKIM, and DMARC. Also, monitor your sender reputation using Microsoft's SNDS program. Encourage recipients to add you to their safe sender list.

February 2023 - Mailjet
Marketer view

Email marketer from SendGrid states that low user engagement (low open rates, click rates) can negatively impact deliverability. Microsoft considers engagement metrics when filtering emails. Focus on sending relevant content to engaged recipients to improve your sender reputation.

May 2023 - SendGrid
Marketer view

Email marketer from Litmus shares that a negative domain reputation can affect deliverability even with a good IP. A poor sending history, low engagement, or being listed on blocklists can harm your domain's reputation. Regularly audit your sending practices to maintain a positive reputation.

September 2024 - Litmus
Marketer view

Email marketer from Sender states that to improve your Hotmail reputation, focus on sending relevant and engaging content. High engagement rates (opens, clicks) signal to Microsoft that your emails are valuable and not spam. Avoid spam trigger words and phrases.

July 2023 - Sender
Marketer view

Email marketer from the Email Marketing Forum explains it could be a problem with the feedback loop. If enough recipients mark your emails as 'junk,' even if they initially land in the inbox, Outlook will learn to filter your emails as spam for other users.

April 2024 - Email Marketing Forum
Marketer view

Email marketer from Reddit shares that it could be a content issue. Outlook/Hotmail might be flagging specific words or phrases in your email as spam, even if your IP reputation is good. Try A/B testing different subject lines and body content.

November 2021 - Reddit
Marketer view

Marketer from Email Geeks suggests to check if the messages are landing in the inbox and then moving to the junk folder shortly after, which is different from landing directly in junk. Look for the header "X-Microsoft-Antispam-Mailbox-Delivery" and check for dest:J (junk) or dest:I (inbox).

May 2021 - Email Geeks
Marketer view

Marketer from Email Geeks shares advice for warming up an IP, including focusing on those who open/click, not increasing volumes until it improves, and opening a ticket with Microsoft if nothing changes after several days.

February 2023 - Email Geeks
Marketer view

Email marketer from ZeroBounce responds to use proper email list hygiene. Regularly clean your email list to remove invalid or inactive email addresses. Sending to a clean list improves your sender reputation and reduces the likelihood of being marked as spam.

August 2022 - ZeroBounce

What the experts say
4Expert opinions

Even with a good IP reputation, emails can still end up in Outlook/Hotmail's junk folder. If messages are delivered to the bulk folder, recipients need to move them to the inbox. Warming up a new IP should focus on users who have already engaged. Maintaining a good sender reputation requires adhering to Microsoft's guidelines, monitoring SNDS data, and addressing issues promptly. Check your IP and domain against blocklists, as being listed can impact deliverability, even with a good IP reputation.

Key opinions

  • User Action Required: If emails land in the bulk/junk folder, recipients moving them to the inbox helps improve future deliverability.
  • Targeted Warmup: During IP warmup, focus on recipients who have previously opened or clicked your emails.
  • SNDS Monitoring: Regular monitoring of Microsoft's Smart Network Data Services (SNDS) is essential for maintaining sender reputation.
  • Blocklist Impact: Being listed on blocklists can negatively impact deliverability to Outlook/Hotmail, even with a good IP reputation.

Key considerations

  • Recipient Education: Encourage recipients to move emails from the junk folder to their inbox if they want to receive future communications.
  • Engagement Focus: Prioritize engaging with recipients who are most likely to interact positively with your emails.
  • Proactive Reputation Management: Actively monitor and address any issues identified through SNDS to maintain a positive sender reputation.
  • Blocklist Checks: Regularly check your IP and domain against common blocklists and take steps to be removed if listed.
Expert view

Expert from Word to the Wise, Laura Atkins, explains that to maintain a good sender reputation with Microsoft, ensure your sending practices are in line with their guidelines, monitor your SNDS data, and actively address any issues identified to avoid being flagged as spam.

March 2022 - Word to the Wise
Expert view

Expert from Email Geeks shares another solution to warm up a new IP is to focus on the people who have opened and clicked on the new IP and restart the warmup.

June 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that if Hotmail is delivering the message to the bulk folder, the recipients need to move it to their inbox.

September 2021 - Email Geeks
Expert view

Expert from Spamresource.com explains that if you are having deliverability problems, check your IP and domain against common blocklists using a tool like MultiRBL. Listing on a blocklist, even if your IP reputation appears good elsewhere, can significantly impact email deliverability to Outlook/Hotmail.

March 2023 - Spamresource.com

What the documentation says
5Technical articles

Even with a good IP reputation, emails can still land in the junk folder due to various factors including negative domain reputation, problematic content, and user interactions. It's crucial to monitor Microsoft's Smart Network Data Services (SNDS) to understand how Microsoft views your IP reputation. Authentication, consistent IP usage, low complaint rates, and avoiding blocklists are vital. Also, pay attention to feedback loops from ISPs to identify problematic users or content that triggers spam reports.

Key findings

  • Multiple Factors Affect Deliverability: Even with a good IP reputation, domain reputation, content, and user interactions play a significant role in email deliverability.
  • Importance of SNDS: Microsoft's Smart Network Data Services (SNDS) provides specific insights into your reputation with Microsoft, which may differ from other services.
  • Authentication is Key: Proper email authentication is crucial for preventing emails from being marked as spam.
  • Consistent Sending Practices: Using a consistent IP address and maintaining low complaint rates improves deliverability.
  • Feedback Loops: ISPs providing you with feedback data allows you to identify problematic sending patterns.

Key considerations

  • Domain Reputation Management: Actively manage and monitor your domain reputation alongside your IP reputation.
  • Content Optimization: Review and optimize email content to avoid triggering spam filters.
  • Regular SNDS Review: Implement a process for regularly monitoring SNDS data to proactively address potential issues.
  • Proactive Blocklist Monitoring: Ensure you domain and IP is not on any blocklists and monitor this regulary.
  • Feedback Loop Processes: Implement processes for using feedback loops to identify and address problematic users or content.
Technical article

Documentation from Microsoft Learn explains that several factors can cause emails to land in the Junk Email folder, including the sender's IP address reputation, domain reputation, content of the message, and user interactions. Even with a good IP reputation, negative domain reputation or problematic content can trigger the junk filter.

January 2024 - Microsoft Learn
Technical article

Documentation from SparkPost explains that Microsoft's Smart Network Data Services (SNDS) provides data about your IP address reputation with Microsoft. Monitoring this helps identify if Microsoft is throttling your mail or marking it as spam, even if other services show a good reputation.

May 2022 - SparkPost
Technical article

Documentation from RFC outlines the processes that should be undertaken around feedback loops with senders. When ISPs and mail providers provide you with feedback data this can be used to identify problematic users or content that is resulting in spam reports.

February 2025 - RFC
Technical article

Documentation from Microsoft advises to use the Smart Network Data Services (SNDS) program to monitor your IP address reputation. This tool can provide insights into why your emails are being filtered as spam, even if your IP reputation seems good elsewhere.

January 2024 - Microsoft
Technical article

Documentation from Google Workspace shares to authenticate email, use a consistent IP address to send emails, keep complaint rates low, and ensure the sending domain or IP address isn't listed on any blocklists.

January 2025 - Google Workspace