Summary
Emails are likely being filtered as spam by Hotmail due to a combination of factors involving sender reputation, email authentication, content, list management, and Microsoft's specific filtering policies. A low sender reputation, influenced by high bounce and complaint rates, can lead to emails being flagged as spam. Failing to properly authenticate emails using SPF, DKIM, and DMARC also contributes to deliverability issues. Content that includes spam trigger words, high image-to-text ratios, or is not personalized can trigger spam filters. Poor list management practices, such as not using double opt-in and making unsubscribing difficult, increase the likelihood of spam complaints. Finally, Microsoft's specific filtering criteria, including their SmartScreen filter and potentially limited responsiveness to sender feedback, necessitate careful adherence to best practices and monitoring of deliverability metrics. It's also worth noting that Microsoft appears to have migrated from Hotmail to Outlook Protection impacting email filtering.
Key findings
- Sender Reputation is Key: A low sender reputation is one of the most significant factors leading to emails being marked as spam in Hotmail.
- Authentication Matters: Failure to properly implement SPF, DKIM, and DMARC can cause emails to be flagged as unauthenticated and sent to spam.
- Content Optimization: Using spam trigger words, having high image-to-text ratios, and lacking personalization can trigger spam filters.
- List Management is Crucial: Poor list management practices, such as not using double opt-in and making unsubscribing difficult, lead to higher spam complaint rates.
- Microsoft's Filtering System: Microsoft uses its SmartScreen filter, combining reputation, content, and user feedback to determine if an email is spam.
- Microsoft Transitioned: Microsoft has transitioned from the Hotmail infrastructure to Outlook Protection which may impact email filtering.
Key considerations
- Monitor Sender Reputation: Regularly monitor your domain and IP reputation using tools like SenderScore and Talos to identify and address deliverability issues proactively.
- Implement SPF, DKIM, and DMARC: Ensure you have correctly implemented SPF, DKIM, and DMARC to authenticate your emails and prevent spoofing.
- Optimize Email Content: Avoid spam trigger words, maintain a healthy image-to-text ratio, and personalize your email content to improve engagement.
- Practice Good List Management: Use double opt-in for subscriptions, provide a clear unsubscribe link, and segment your email list to send more targeted content.
- Monitor Blocklists: Check regularly to see if your IP or domain is on any blocklists and take action to get removed if necessary.
- Engage with Microsoft: Consider filling out the Microsoft mitigation form if you are confident you are not engaging in spam practices.
- Monitor Feedback Loops: Monitor feedback loops to identify and address problematic subscribers from your list.
What email marketers say
14 marketer opinions
Emails are likely going to the spam box in Hotmail (Outlook) due to a combination of factors related to sender reputation, email content, authentication, and user engagement. Microsoft uses sophisticated filtering systems that evaluate sender reputation based on metrics like bounce rates, complaint rates, and engagement. Poor reputation, being blacklisted, or failing to authenticate emails properly (SPF, DKIM, DMARC) can result in spam placement. Content issues, such as using spam trigger words, high image-to-text ratios, and lack of personalization, can also trigger filters. Additionally, not adhering to best practices for list management, such as using double opt-in and providing easy unsubscribe options, contributes to deliverability problems. Engaging with Microsoft's mitigation form and actively monitoring and improving sender reputation are crucial.
Key opinions
- Sender Reputation: Low sender reputation is a primary cause for emails landing in Hotmail's spam folder. This is influenced by bounce rates, complaint rates, and engagement metrics.
- Authentication: Incorrect or missing SPF, DKIM, and DMARC records can cause emails to fail authentication checks, leading to spam placement.
- Content: Spam trigger words, high image-to-text ratios, and non-personalized content increase the likelihood of emails being marked as spam.
- List Management: Poor list management practices, such as not using double opt-in and making unsubscribing difficult, contribute to higher spam complaint rates.
- Microsoft Mitigation: Engaging with Microsoft through their mitigation form may help to improve inbox placement if the sender is not engaging in spam practices.
- Infrastructure Change: Microsoft's shift to Outlook Protection has changed the way their filtering works.
Key considerations
- Monitor Reputation: Regularly check your domain and IP reputation using tools like SenderScore and Talos to identify and address deliverability issues proactively.
- Authenticate Emails: Implement and maintain SPF, DKIM, and DMARC records to authenticate your emails and prevent spoofing.
- Optimize Content: Avoid spam trigger words, maintain a balanced image-to-text ratio, and personalize your email content to improve engagement.
- Manage Lists: Use double opt-in for subscriptions, provide a clear and easy-to-find unsubscribe link, and segment your email list for more targeted content.
- Warm Up IPs/Domains: Warm up new IPs or domains gradually by increasing sending volume over time to build a positive reputation.
- Feedback Loops: Monitor feedback loops from email providers like Hotmail to identify and remove problematic subscribers.
- Mitigation Form: Use the mitigation form when appropriate.
Marketer view
Email marketer from Webmaster Forum suggests segmenting your email list to send more targeted and relevant content to subscribers. Sending the same email to everyone can increase spam complaints and negatively affect your sender reputation with Hotmail.
27 Sep 2021 - Webmaster Forum
Marketer view
Email marketer from Email Geeks shares that if you're being put in the spam folder, your best bet is to fill out the mitigation form and make your case.
10 Aug 2022 - Email Geeks
What the experts say
6 expert opinions
Experts suggest that Hotmail/Outlook's spam filtering is influenced by several factors including sender reputation, email content, and user feedback. Microsoft's SmartScreen filter analyzes these signals to determine whether an email should be placed in the inbox or spam folder. Maintaining a good sender reputation by monitoring bounce rates, complaint rates, and engagement metrics is crucial. Additionally, it's important to ensure your IP or domain is not on any blocklists. Microsoft often prioritizes its own filtering preferences over sender feedback, making it essential to adhere to their guidelines.
Key opinions
- Microsoft's Filtering Criteria: Microsoft uses a combination of sender reputation, content analysis, and user feedback to filter emails.
- Importance of Sender Reputation: Maintaining a good sender reputation is crucial for avoiding the spam folder at Hotmail.
- Microsoft's Stance: Microsoft tends to prioritize its own filtering preferences over sender feedback, making it difficult to influence their decisions.
- Blocklist Impact: Being on blocklists can significantly impact email deliverability to Hotmail.
- SmartScreen Analysis: Microsoft's SmartScreen filter analyzes various signals to filter spam, including sender reputation and content.
Key considerations
- Monitor Sender Reputation: Regularly monitor bounce rates, complaint rates, and engagement metrics to maintain a good sender reputation.
- Check Blocklists: Regularly check if your IP or domain is on any blocklists and take steps to get removed if necessary.
- Focus on Content: Ensure that your email content is not triggering spam filters by avoiding spam trigger words and maintaining a good image-to-text ratio.
- Adapt to Microsoft's Preferences: Be aware that Microsoft prioritizes its filtering preferences, and adjust your email practices accordingly.
- Wanted Mail: Focus on sending wanted mail.
Expert view
Expert from Spam Resource explains that Microsoft's SmartScreen filter analyzes various signals, including sender reputation, content, and user complaints, to filter spam. They suggest that senders focus on building a good reputation by sending wanted mail and avoiding spam traps.
13 Mar 2022 - Spam Resource
Expert view
Expert from Spam Resource explains that Microsoft (Hotmail/Outlook) uses a combination of reputation, content, and user feedback to determine if an email should be placed in the inbox or spam folder. They advise checking your sender reputation and ensuring that your email content is not triggering spam filters.
29 Nov 2023 - Spam Resource
What the documentation says
5 technical articles
Documentation emphasizes the importance of adhering to email best practices and standards to ensure deliverability to Hotmail. Strict policies regarding spam and unsolicited email require senders to focus on email authentication (SPF, DKIM, DMARC), proper list management, and content creation. Correctly formatted emails following IETF standards, along with robust authentication methods, help prevent spoofing and improve deliverability. Monitoring DMARC reports aids in identifying and addressing any authentication failures.
Key findings
- Strict Policies: Outlook.com has strict policies regarding spam and unsolicited email that senders must adhere to.
- Email Authentication: SPF, DKIM, and DMARC are crucial for authenticating emails and preventing spoofing.
- Best Practices: Following best practices for email authentication, list management, and content creation is essential for deliverability.
- IETF Standards: Adhering to IETF standards for email formatting and transmission ensures proper interpretation by spam filters.
- DMARC Monitoring: Implementing DMARC and monitoring reports can help identify and address authentication failures.
Key considerations
- Implement SPF: Create and maintain an accurate SPF record for your domain to authenticate your emails.
- Implement DKIM: Implement DKIM to digitally sign your messages and allow email receivers to verify their authenticity.
- Implement DMARC: Implement DMARC to provide a policy that tells email receivers what to do with emails that fail authentication checks and monitor DMARC reports.
- Adhere to IETF Standards: Ensure your emails follow IETF standards for formatting and transmission.
- Monitor Metrics: Keep your bounce rates and spam complaints low as they can result in IP or domain blacklisting.
Technical article
Documentation from DKIM explains that DomainKeys Identified Mail (DKIM) provides an email authentication system that allows email senders to digitally sign their messages, which email receivers can then verify. Implementing DKIM can significantly improve email deliverability to Hotmail by proving email authenticity.
18 Jul 2021 - DKIM
Technical article
Documentation from DMARC.org explains that Domain-based Message Authentication, Reporting & Conformance (DMARC) builds upon SPF and DKIM to provide a policy that tells email receivers what to do with emails that fail authentication checks. Implementing DMARC and monitoring reports can help identify and address spoofing attempts, improving deliverability to Hotmail.
26 Nov 2021 - DMARC.org
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