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How can I diagnose and resolve email deliverability issues when emails aren't reaching intended recipients?

Summary

Diagnosing and resolving email deliverability issues requires a comprehensive strategy encompassing technical setup, sending practices, and content optimization. Key steps include verifying sender authentication (SPF, DKIM, DMARC), monitoring sender reputation using tools like Google Postmaster Tools, and analyzing Non-Delivery Reports (NDRs) to identify delivery failures. High spam complaint rates, especially related to cold emails, negatively impact deliverability. Mitigation strategies involve warming up IP addresses, cleaning email lists, segmenting lists for targeted messaging, and personalizing email content. Regularly checking IP addresses against blacklists, using tools like Mail-Tester to assess spam scores, and monitoring inbox placement across different email providers are also crucial. Separating infrastructure for cold emails helps protect the primary domain's reputation. Analyzing DMARC reports aids in identifying and addressing authentication failures and spoofing attempts. Determining whether emails land in spam or are blocked directs troubleshooting efforts.

Key findings

  • Authentication is Key: Valid SPF, DKIM, and DMARC configurations are crucial for sender verification and trust.
  • Monitor Reputation: Regularly monitor sender reputation using tools like Google Postmaster Tools.
  • Address Spam Complaints: High spam complaint rates significantly harm deliverability; aim for rates below 0.1%.
  • Cold Email Isolation: Separate cold email infrastructure from primary domain to protect reputation.
  • List Hygiene Matters: Regularly clean and segment email lists to improve engagement and reduce bounces.
  • Content Optimization is Important: Personalized, engaging, and mobile-friendly content reduces spam flags.
  • Analyze NDRs: Non-Delivery Reports provide insights into why emails fail to deliver.
  • Blacklist Awareness: Regularly check IPs and domains against blacklists to address reputation issues.
  • Delivery Destination Analysis: Determine if emails are going to spam or being blocked entirely to guide troubleshooting.
  • DMARC Reporting: DMARC reporting offers a method of identifying if emails are authentic.

Key considerations

  • Verify Authentication: Thoroughly verify SPF, DKIM, and DMARC configurations.
  • Implement Reputation Monitoring: Consistently monitor sender reputation using available tools.
  • Manage Spam Complaints: Address and reduce spam complaints through improved sending practices.
  • Isolate Cold Emails if Possible: Separate cold email activities onto a separate domain and infrastructure.
  • Practice List Hygiene: Maintain a clean and engaged email list through regular cleaning and segmentation.
  • Optimize Content: Create personalized and engaging email content.
  • Analyze and Understand NDRs: Review NDRs to understand why email deliveries fail.
  • Blacklist Management: Be aware of and manage any potential listings on blacklists.
  • Determine Delivery Path: Determine is emails are going into spam or being blocked.
  • Implement DMARC Analysis: Review DMARC reports regularly.

What email marketers say

15 marketer opinions

Diagnosing and resolving email deliverability issues involves a multi-faceted approach. It begins with verifying sender authentication (SPF, DKIM, DMARC) and monitoring sender reputation through tools like Google Postmaster Tools. High spam complaint rates, often linked to sending cold emails, significantly impact deliverability. Strategies to mitigate this include warming up IP addresses, cleaning email lists by removing inactive subscribers, segmenting lists for targeted messaging, and personalizing email content to increase engagement. Checking IP addresses against blacklists and using tools like Mail-Tester to assess spam scores are also crucial. Finally, monitoring inbox placement across different email providers and A/B testing email content enhances deliverability and overall email performance.

Key opinions

  • Authentication: Properly configured SPF, DKIM, and DMARC are essential for verifying sender identity and preventing spoofing.
  • Sender Reputation: Monitoring sender reputation via tools like Google Postmaster Tools is critical for identifying and addressing deliverability issues.
  • Spam Complaints: High spam complaint rates negatively impact deliverability; aim for a rate below 0.1%.
  • Cold Emails: Sending cold emails can increase the risk of deliverability issues; consider warming up IPs and using separate sending domains.
  • List Hygiene: Regularly clean email lists to remove inactive subscribers and reduce bounce rates and spam complaints.
  • Content Optimization: Personalizing email content, A/B testing subject lines, and ensuring mobile-friendliness can improve engagement and deliverability.
  • Blacklist Checks: Regularly check your IP and domain against email blacklists to identify potential issues.
  • Deliverability Testing: Use tools like Mail-Tester and mailbox placement tests to assess email spam scores and inbox placement across different providers.

Key considerations

  • Authentication Setup: Ensure SPF, DKIM, and DMARC records are correctly configured to avoid authentication failures.
  • Spam Complaint Monitoring: Continuously monitor spam complaint rates and take immediate action to address any issues.
  • Email List Management: Implement a double opt-in process and regularly clean your email list to maintain a healthy subscriber base.
  • Content Relevance: Personalize email content and segment your audience to improve engagement and reduce the likelihood of being marked as spam.
  • Sending Practices: Warm up new IP addresses and sending domains to build a positive sender reputation gradually.
  • Provider-Specific Issues: Monitor inbox placement across different email providers to identify and address any provider-specific deliverability issues.
  • Blacklist Monitoring: Set up alerts to be notified if your IP or domain is blacklisted, and act quickly to resolve the issue.
  • Engagement Matters: Focus on strategies that increase user engagement like mobile-friendly emails and A/B testing of subject lines.

Marketer view

Marketer from Email Geeks shares Google Postmaster Tools for monitoring sender reputation at Gmail and notes that cold emails often cause deliverability issues. They also state that the user reported spam rate is quite high and the risk threshold for spam complaints is about 0.1%, and per that graph they are averaging 0.5% to 1.5%.

28 Jan 2022 - Email Geeks

Marketer view

Email marketer from Sendinblue suggests warming up your IP address, cleaning your email list regularly to remove inactive subscribers, and personalizing your email content to increase engagement and avoid spam filters.

15 Oct 2022 - Sendinblue

What the experts say

5 expert opinions

Diagnosing and resolving email deliverability problems requires a thorough examination of factors ranging from the technical setup to sending practices. A crucial first step is determining whether emails are being delivered to the spam folder or being blocked outright, as each scenario points to different underlying issues. Properly configuring and validating email authentication records (SPF, DKIM, DMARC) is essential, as misconfigurations are a common cause of deliverability failures. Regularly checking your sending IP and domain against email blacklists is also vital for identifying potential reputation problems. Furthermore, using a separate infrastructure for cold emails can prevent deliverability issues from impacting your primary domain. Analyzing DMARC reports helps identify authentication failures and spoofing attempts, and adjusting DMARC policies to quarantine or reject suspicious emails can improve deliverability and protect against domain abuse.

Key opinions

  • Spam vs. Blocked: Determining whether emails land in spam or are blocked entirely directs troubleshooting efforts.
  • Authentication: Validating and correctly configuring SPF, DKIM, and DMARC is essential for email deliverability.
  • Blacklist Monitoring: Regularly checking against email blacklists identifies potential reputation issues.
  • Cold Email Infrastructure: Using a separate infrastructure for cold emails protects the primary domain's reputation.
  • DMARC Analysis: Analyzing DMARC reports aids in identifying and mitigating authentication failures and spoofing.

Key considerations

  • Determine Delivery Status: First, confirm if emails are being delivered to the spam folder or blocked entirely, as this informs the next steps.
  • Validate Authentication Records: Carefully validate SPF, DKIM, and DMARC settings to ensure correct configuration.
  • Monitor Blacklists Regularly: Implement a process for regularly checking against blacklists and address any issues promptly.
  • Isolate Cold Email Campaigns: Consider setting up a separate infrastructure and domain specifically for cold email campaigns.
  • Review DMARC Reports: Regularly review DMARC reports and adjust policies to enhance security and deliverability.

Expert view

Expert from Word to the Wise suggests reviewing DMARC reports to identify authentication failures and potential spoofing attempts, and adjusting the DMARC policy to 'quarantine' or 'reject' to improve deliverability and protect against domain abuse.

3 Mar 2024 - Word to the Wise

Expert view

Expert from Email Geeks advises setting up a separate infrastructure, including a different domain, for cold emails if they are being sent on the same domain as the corporate domain. They also mention that Google Postmaster data doesn't include information for Google Workspace accounts, only @gmail.com addresses.

13 Jul 2022 - Email Geeks

What the documentation says

4 technical articles

Diagnosing and resolving email deliverability issues involves several key technical aspects. Verifying sender authentication using SPF, DKIM, and DMARC is crucial to establish trust with receiving mail servers and prevent spoofing. Analyzing Non-Delivery Reports (NDRs) helps identify delivery failures caused by issues like incorrect addresses or full mailboxes. Implementing DMARC protects against spoofing and phishing by providing a policy for handling emails that fail authentication checks. Monitoring domain reputation through tools like Google Postmaster Tools is also important for identifying and addressing potential deliverability problems.

Key findings

  • Authentication Verification: Verifying SPF, DKIM, and DMARC is essential for establishing sender legitimacy and preventing spoofing.
  • NDR Analysis: Analyzing Non-Delivery Reports (NDRs) reveals reasons for email delivery failures.
  • DMARC Implementation: Implementing DMARC protects against spoofing and phishing by defining how to handle emails failing authentication.
  • Reputation Monitoring: Monitoring domain reputation helps identify and address deliverability issues.

Key considerations

  • Sender Authentication: Ensure SPF, DKIM, and DMARC are properly configured and validated.
  • NDR Review: Regularly review NDRs to identify and resolve delivery failure causes.
  • DMARC Policy: Establish a DMARC policy to manage emails that fail SPF or DKIM checks.
  • Reputation Monitoring Tools: Utilize tools like Google Postmaster Tools to track domain reputation and identify issues proactively.

Technical article

Documentation from Google Workspace Admin Help emphasizes verifying sender authentication (SPF, DKIM, DMARC), avoiding sending unsolicited email, and monitoring your domain's reputation using Google Postmaster Tools to diagnose deliverability issues.

16 Feb 2025 - Google Workspace Admin Help

Technical article

Documentation from RFC explains that SPF records help prevent email spoofing by specifying which mail servers are authorized to send email on behalf of your domain. Configuring SPF correctly is crucial for improving email deliverability.

12 Apr 2024 - RFC

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