How to troubleshoot emails landing in spam despite passing DKIM, SPF, and DMARC?

Key findings

• Authentication is not the only factor: Passing SPF, DKIM, and DMARC does not automatically guarantee inbox placement; other factors like sender reputation, content, and engagement play significant roles.
• Seed list limitations: Deliverability vendors using seed lists might show 100% inboxing, but these results may not accurately reflect actual recipient inbox placement, especially if engagement metrics are low.
• Internal vs. external delivery: Emails landing in internal team spam folders (e.g., Gmail) might be due to specific internal or local filters rather than a widespread deliverability issue affecting all subscribers.
• BIMI's role: While BIMI (Brand Indicators for Message Identification) enhances brand trust and visibility, it is not a direct solution for emails landing in spam folders when authentication already passes.

Key considerations

• Analyze engagement metrics: High open rates (e.g., 40%+) typically suggest good inbox placement. If your actual open rates are lower, it points to an engagement or reputation issue.
• Check local filters: Investigate if your internal team's email clients or corporate network have specific filters that might be redirecting your legitimate emails to spam, especially if they don't originate from your MX records.
• Utilize postmaster tools: Implement tools like Google Postmaster Tools to gain insight into domain reputation, spam rates, and authentication errors directly from major ISPs.
• Review email content: Even with perfect authentication, spammy content, broken links, or excessive images can trigger filters. Use an email deliverability tester to check your email's spam score.

Key opinions

• Frustration with authentication alone: Marketers frequently express confusion and frustration when emails pass all authentication checks but still encounter spam filtering.
• Discrepancy in reporting: There's a common observation that deliverability services using seed lists may report 100% inboxing, yet actual sends to internal teams or subscribers land in spam.
• Questioning additional measures: Some marketers inquire about the effectiveness of additional protocols like BIMI for improving deliverability, despite understanding its primary function isn't spam avoidance.
• Platform-specific challenges: Issues are often noted with specific sending platforms, such as Salesforce Marketing Cloud, and their interaction with receiving ISPs.

Key considerations

• Review subscriber engagement: A primary area of focus should be actual open rates and engagement metrics. If these are low, it can override positive authentication signals, pointing to a reputation issue rather than a technical one.
• Assess seed list accuracy: While useful, seed list data should be compared with real-world inboxing and engagement to detect discrepancies, especially for specific recipient domains.
• Consider local filtering: If only internal team members are receiving emails in spam, investigate specific email client settings or corporate network filters (e.g., related to MX record validation) that might be marking your emails as junk.
• Verify email type: Identify whether the emails are marketing, transactional, or peer-to-peer, as different types of email can have varying deliverability challenges and expectations from ISPs.

Key opinions

• BIMI is not the solution: Experts explicitly state that BIMI is not a fix for emails landing in spam, as its purpose is brand display, not deliverability improvement.
• Engagement and reputation are key: The primary drivers for inbox placement, even with strong authentication, are sender reputation and recipient engagement, including open rates and complaint rates.
• Importance of postmaster tools: Setting up and regularly checking Google Postmaster Tools is considered crucial for diagnosing deliverability issues for Gmail recipients.
• Beyond seed lists: Relying solely on seed list data for deliverability assessment can be misleading; actual engagement data and ISP feedback loops provide a more accurate picture.

Key considerations

• Leverage postmaster data: Actively use Google Postmaster Tools to monitor domain reputation, spam complaints, and other critical metrics that affect inbox placement, particularly for Gmail.
• Address engagement issues: If open rates are low, focus on improving list hygiene, segmenting recipients, and optimizing content to boost engagement and subsequently, sender reputation.
• Content and infrastructure review: Even with correct authentication, review your email content for spam triggers and ensure your sending infrastructure (e.g., dedicated IP, shared IP reputation) is not impacting delivery. You can often see this in email logs and headers.
• Understand ISP nuances: Different ISPs have varying filtering rules. What works for one may not work for another. Monitor ISP-specific feedback to fine-tune your strategy.

Key findings

• Authentication is a baseline: SPF, DKIM, and DMARC ensure sender legitimacy, but they are just one component of a complex deliverability ecosystem.
• DMARC policy impact: DMARC policies dictate how receiving servers should treat emails that fail SPF or DKIM, but they don't explicitly guarantee inboxing for passing emails.
• Beyond technical checks: Mailbox providers use sophisticated algorithms that consider sender reputation, email content, recipient engagement, and blocklist status even if authentication passes.
• Configuration nuances: Even with SPF and DKIM correctly set up, subtle misconfigurations or unforeseen interactions can still lead to deliverability issues.

Key considerations

• Holistic deliverability view: Focus on a comprehensive deliverability strategy that includes list hygiene, content optimization, sending frequency, and monitoring engagement, not just authentication.
• Content best practices: Adhere to best practices for email content, avoiding spam trigger words, excessive links, or poorly formatted HTML, regardless of authentication success.
• Monitor sender reputation: Actively track your sender reputation across various ISPs, as a poor reputation can lead to blocklisting or direct spam folder placement, even with passing authentication.
• Review email headers: Examine the full email headers (including authentication results, spam scores, and receiving server notes) for clues when troubleshooting, as they often provide specific reasons for spam placement.