What does a red filter result in SNDS mean, and how does it relate to email deliverability and SmartScreen?

Key findings

• SmartScreen assessment: The red filter result specifically refers to how SmartScreen, Microsoft's content filter, perceives your email content. It suggests your messages are highly likely to be considered spam based on content analysis.
• Inconsistent correlation: A red SNDS filter result doesn't always mean your emails are going straight to the junk folder. Your overall IP and domain reputation can still lead to inbox placement, even if SmartScreen flags your content.
• Content focus: Low complaint rates or zero spam trap hits in SNDS, alongside a red filter, point towards content-related issues as the primary culprit, rather than list quality or sending practices.
• User settings impact: Individual user settings, such as safelists or custom filtering rules, can override SmartScreen's verdict, allowing some flagged emails to still reach the inbox.
• Data point, not final judgment: Microsoft's own documentation states that the filter result is only one data point to help paint a picture, not a final judgment.

Key considerations

• Don't panic: While a red filter is a warning sign, it does not automatically mean all your mail is going to spam. For more insights on this, you can read about why outlook.com email deliverability is inconsistent.
• Verify inbox placement: Send test emails to Outlook.com addresses and monitor their actual placement. This provides more concrete data than SNDS colors alone.
• Review content extensively: Focus on elements that SmartScreen might deem suspicious. This includes URLs, HTML coding, image-to-text ratio, and common spam trigger words. Consider why emails go to spam after changing content templates.
• Monitor engagement: Look at open and click rates for Microsoft recipients. A drop in these metrics is a stronger indicator of deliverability issues than a red filter result alone. You can find more information about understanding sender reputation in this Mailgun blog post on Microsoft SNDS.

Key opinions

• SNDS colors are deceptive: Many marketers believe that the colored alerts in SNDS, including red, do not always accurately reflect actual delivery outcomes (inbox vs. spam folder).
• Content is the trigger: A common sentiment is that a red filter result points to SmartScreen's (Microsoft's content filter) issues with email content, even if IP and domain reputation are otherwise good.
• Low complaints can be misleading: Marketers note that a low feedback loop (FBL) complaint rate can occur because emails are already going to the spam folder, preventing recipients from reporting them as spam.
• Direct testing is key: Sending test emails to Outlook.com inboxes is often recommended as a more reliable way to verify actual inbox placement than solely relying on SNDS data.

Key considerations

• Independent verification: Do not rely solely on SNDS colors. Instead, perform your own tests to Outlook.com inboxes to see where your emails land. This is important for common issues with Microsoft SNDS.
• Content optimization: If SmartScreen is flagging your mail, thoroughly review your email content, including subject lines, body text, image-to-text ratio, and especially the URLs within your emails.
• HTML and coding: Check your email's HTML structure and coding. Poorly coded emails can sometimes trigger spam filters, including SmartScreen.
• Engagement correlation: Pay close attention to engagement metrics for Microsoft recipients. A decline in opens or clicks often provides a clearer picture of deliverability issues than a red SNDS status. The HighLevel Support Portal also describes how one or more red days in SNDS indicates higher spam rates.

Key opinions

• Content-centric filtering: The red filter result is primarily an indicator of SmartScreen's negative assessment of your email content, not a direct block of your IP address or domain.
• Holistic view needed: Relying solely on SNDS colors is insufficient. Experts suggest considering other factors like engagement rates, spam trap hits, and complaint rates for a complete picture of deliverability.
• Nuance of red vs. block: A red SmartScreen filter result means mail is likely spam, but it is distinct from an outright block, which would prevent mail from being received at all.
• Impact on user experience: Even if mail lands in the inbox, a red SmartScreen classification can lead to a lower sender score with Microsoft, potentially impacting future deliverability to new recipients.

Key considerations

• Deep content analysis: When SmartScreen is the problem, focus on your content strategy, including message tone, image usage, and link reputation. This is key to troubleshooting Microsoft email deliverability issues.
• Sender reputation: Recognize that sender reputation is a multifaceted score. A red SmartScreen filter result contributes negatively, even if other factors (like IP reputation) seem stable.
• Segment and test: If a red filter persists, try segmenting your audience and testing different content variations to identify what specific elements trigger SmartScreen. You can learn more about Microsoft SCL and BCL ratings.
• Consistency matters: Consistent sending of wanted mail, even with minor SmartScreen flags, helps build a positive sender profile over time. Avoid drastic content changes that could trigger harsher filtering. Abnormal AI explains how email filters work to stop spam.

Key findings

• Aggregate results: The filter result reflects the combined outcome of spam filtering for all messages sent by an IP during a specific period.
• Nuanced interpretation: Microsoft indicates that no spam filter is perfect, reinforcing that the filter result is a guide, not an absolute truth.
• Verdict calculation: The colors are defined by the percentage of time a spam verdict is rendered. Importantly, one message to ten recipients counts as ten verdicts, not one.
• No direct inbox representation: The result does not directly represent deliveries to users' inboxes or junk folders, as individual user settings can alter final placement.
• Safelist exceptions: Messages on a user's safelist may bypass filtering, meaning the filter result doesn't account for mail that might have been caught but wasn't due to such settings.

Key considerations

• Interpret carefully: Understand that a red filter result from SmartScreen is a strong indicator of content issues, but it should be cross-referenced with other deliverability metrics.
• Focus on content: Given that SmartScreen is a content filter, significant effort should be placed on optimizing email content, including text, images, and links. This impacts how email filters affect inbox placement.
• Acknowledge user control: Be aware that user-specific settings can override filtering decisions, complicating direct correlation between SNDS data and observed inbox placement.
• Combine data sources: Integrate SNDS data with other deliverability tools and internal metrics (like open rates to Microsoft domains) to gain a more accurate understanding of your performance. Learn more about solving Microsoft deliverability issues.