How to troubleshoot deliverability issues when ESP and corporate email domains are the same?

Key findings

• Reputation confusion: Spam filters may incorrectly classify legitimate corporate emails as marketing or bulk mail if they originate from the same domain and share reputation. Domain reputation is key.
• Authentication issues: Improperly configured SPF, DKIM, and DMARC records can cause emails to fail authentication checks, especially when multiple sending sources (like an ESP and internal mail server) use the same domain. Learn how to fix DMARC settings.
• Sending pattern differences: Marketing emails often have higher volumes, different content, and higher bounce/complaint rates compared to corporate emails. Mixing these can degrade the overall domain reputation.
• Blocklisting risk: If marketing emails trigger blocklists (also known as blacklists), the entire corporate domain may suffer, leading to widespread deliverability failures. Understand your email domain reputation.

Key considerations

• Domain separation: Consider using subdomains for marketing or bulk emails (e.g., marketing.yourdomain.com) to isolate their sender reputation from your main corporate domain.
• Robust authentication: Ensure SPF, DKIM, and DMARC records are correctly configured for both your corporate mail server and your ESP, authorizing all legitimate sending sources.
• Consistent sending practices: Maintain good sending habits for marketing emails, including list hygiene, relevant content, and managing bounce and complaint rates.
• Monitoring and feedback loops: Actively monitor DMARC reports and sign up for ISP feedback loops to quickly identify and address deliverability issues.

Key opinions

• Subdomain adoption: Many marketers advocate for using subdomains for marketing emails to safeguard the main corporate domain's reputation. Subdomains encounter fewer problems.
• List hygiene focus: Regularly cleaning email lists to remove invalid or unengaged subscribers is a top priority to reduce bounce rates and spam trap hits.
• Content relevance: Ensuring email content is highly relevant and valuable to recipients helps reduce complaints and improves engagement metrics.
• Campaign monitoring: Closely monitoring campaign performance, including open rates, click-through rates, and complaint rates, is essential for early detection of issues. Run an email deliverability test.

Key considerations

• Brand consistency vs. deliverability: While using the same domain provides brand consistency, it often poses a significant deliverability risk that needs careful mitigation. Changing your domain could be extreme.
• Collaboration with IT: Effective troubleshooting and long-term success require close cooperation between marketing and IT teams, especially regarding DNS records and authentication.
• Impact on corporate mail: Marketing activity needs to be managed carefully to avoid negative impacts on critical corporate email communications, like avoiding issues with press releases.
• ESP reputation: Choosing a reputable ESP that actively manages shared IP pools and provides tools for deliverability monitoring is paramount. Use a reputable ESP.

Key opinions

• Isolation through subdomains: Experts consistently recommend using distinct subdomains for marketing and transactional emails to isolate their individual reputations. This is part of a simple guide to email authentication.
• Authentication enforcement: Proper implementation and alignment of SPF, DKIM, and DMARC are non-negotiable for proving sender legitimacy across all sending sources.
• Holistic view: A comprehensive approach to deliverability considers all sending patterns and how they interact to form the overall domain reputation. Check your IP and domain against blocklists.
• Proactive monitoring: Using DMARC reports and ISP feedback loops allows for early detection of authentication failures or reputation degradation.

Key considerations

• DNS configuration: Accurate and up-to-date DNS records for SPF, DKIM, and DMARC are critical for all domains and subdomains used for email sending. Troubleshoot intermittent failures.
• Warming up: When introducing new sending IPs or subdomains, a careful warming-up process is necessary to build a positive reputation gradually.
• Distinguishing email types: ISPs (Internet Service Providers) often differentiate between transactional, marketing, and corporate mail. Understanding this distinction is key to optimizing deliverability.
• Shared IP pools: When using an ESP's shared IP pool, the sender's reputation is influenced by other senders. Choose an ESP with strong sender vetting and management policies.

Key findings

• Standard compliance: Adherence to RFCs and other email standards is fundamental for reliable email delivery and avoiding rejections.
• Authentication requirements: Documentation outlines the necessity of correct SPF, DKIM, and DMARC configurations to verify sender identity and prevent spoofing. Learn about DMARC tags and their meanings.
• DNS accuracy: Accurate and up-to-date DNS records are repeatedly highlighted as critical for email deliverability, with misconfigurations leading to significant issues.
• Sender guidelines: Major email providers publish specific guidelines for senders to ensure optimal inbox placement and avoid being flagged as spam. Comply with Outlook's new requirements.

Key considerations

• DMARC policy application: Implementing a DMARC policy (even at p=none initially) is essential for receiving valuable aggregate reports and forensic data.
• SPF record limitations: Awareness of the SPF 10-lookup limit is crucial, especially when authorizing multiple sending sources under one domain.
• DKIM signing: Ensuring all legitimate mail is signed with a valid DKIM signature that aligns with the sending domain is paramount.
• Feedback loop enrollment: Documentation often encourages senders to enroll in ISP feedback loops to receive complaints directly and manage subscriber lists effectively. Checklist for switching ESPs.