Summary
Optimizing email deliverability during a subdomain migration and addressing Gmail reputation drops requires a multi-faceted approach. Technical setup includes proper SPF, DKIM, and DMARC authentication, maintaining a low spam rate, monitoring IP health with tools like SNDS, and implementing strict DMARC policies. Strategic actions involve gradually increasing sending volume to the new subdomain, beginning with engaged users, and segmenting lists for targeted emails. Crucially, maintain a clean and engaged email list by removing inactive subscribers and validating email addresses. Monitor sender reputation using tools like Google Postmaster Tools and Sender Score. Pay close attention to engagement metrics as low open and click-through rates negatively impact reputation. Signing up for feedback loops aids in identifying and resolving complaints. Testing emails for rendering issues and maintaining consistent sending volumes are also critical. The consensus points to a balanced strategy encompassing technical compliance, data hygiene, and engagement optimization.
Key findings
- Authentication is Key: Proper SPF, DKIM, and DMARC setup is critical for deliverability, especially with Gmail.
- Gradual Warmup: Gradually increase sending volume on the new subdomain, starting with engaged users.
- Data Hygiene Matters: Maintaining a clean and engaged email list is essential; remove inactive subscribers and validate addresses.
- Engagement Drives Reputation: High engagement (open rates, click-through rates) improves sender reputation, while low engagement hurts it.
- Monitor Sender Reputation: Actively monitor sender reputation using tools like Google Postmaster Tools and Sender Score.
- Subdomain Separation: Using separate subdomains for marketing vs. transactional emails helps protect the primary domain.
Key considerations
- Technical Expertise Required: Implementing SPF, DKIM, and DMARC requires technical knowledge and careful configuration.
- Consistent Monitoring: Continuously monitor IP and domain reputation, spam rates, and DMARC reports.
- Targeted Segmentation: Segment your email list based on engagement, demographics, and behavior to send more relevant emails.
- List Validation: Employ email validation services to remove invalid or risky email addresses.
- Feedback Loop Monitoring: Actively monitor and respond to feedback loop complaints to address deliverability issues.
- Avoid Sudden Spikes: Maintain consistent sending volumes to avoid triggering spam filters.
- MTA Configuration: Pay attention to timezone consistency, daily max emails per IP, hourly traffic density, and data quality distribution across MTAs.
- Active vs Inactive Ratio: Keep the total active volume per month higher than the total inactive volume per month.
What email marketers say
14 marketer opinions
Migrating to a new subdomain requires a strategic approach to maintain and improve email deliverability, especially when experiencing reputation drops with Gmail. Key actions include gradually increasing sending volume, starting with engaged users, and authenticating the subdomain with SPF, DKIM, and DMARC. Monitoring sender reputation using tools like Google Postmaster Tools and Sender Score is crucial. Maintaining a clean and engaged email list through regular removal of unengaged subscribers and implementing double opt-in is essential. Segmentation based on engagement and demographics allows for targeted emails. Feedback loops with mailbox providers help identify and address complaints. Thoroughly testing emails for rendering issues, monitoring IP reputation, and avoiding sudden spikes in email activity are also recommended.
Key opinions
- Gradual Warmup: Slowly increase sending volume from the new subdomain, starting with highly engaged users.
- Authentication: Properly authenticate the subdomain using SPF, DKIM, and DMARC to verify email authenticity.
- List Hygiene: Maintain a clean and engaged email list by removing inactive subscribers and using double opt-in.
- Reputation Monitoring: Actively monitor sender reputation using Google Postmaster Tools and Sender Score.
- Segmentation: Segment email lists based on engagement and demographics for targeted, relevant emails.
- Feedback Loops: Use feedback loops with mailbox providers to identify and address complaints and spam reports.
- Engagement Matters: Low engagement campaigns have a larger impact on the entire reputation of the subdomain.
Key considerations
- Data Quality: Assess and improve data quality by removing invalid or inactive email addresses.
- IP Reputation: Monitor IP address reputation and ensure it's not blacklisted during the transition.
- Email Testing: Thoroughly test emails before sending to ensure they render correctly across different devices and clients.
- Consistent Volume: Maintain consistent sending volume and avoid sudden spikes in email activity.
- Content Relevance: Ensure emails are relevant and engaging to recipients to improve deliverability.
- MTA Distribution: Consider timezone consistency, daily max emails per IP, hourly traffic density, and data quality distribution across MTAs.
- Active vs Inactive: Total active volume per month should not be less than total inactive volume per month.
Marketer view
Email marketer from HubSpot Blog states segmenting your email list based on engagement, demographics, and other factors allows you to send more targeted and relevant emails. This can improve engagement rates and overall deliverability. Send targeted emails
23 Jun 2022 - HubSpot Blog
Marketer view
Email marketer from AWeber Blog advises signing up for feedback loops (FBLs) with major mailbox providers like Gmail and Microsoft. FBLs provide valuable information about complaints and spam reports, allowing you to identify and address issues quickly.
27 Aug 2023 - AWeber Blog
What the experts say
3 expert opinions
Experts emphasize the importance of protecting your primary domain's reputation by using separate subdomains for marketing and transactional emails. Gradual volume increases on the new subdomain are crucial for building a positive reputation. Monitoring the IP address reputation of the new subdomain during migration is also vital to prevent blacklisting. Engagement metrics, such as open rates and click-through rates, significantly impact deliverability, with low engagement negatively affecting sender reputation and potentially causing Gmail reputation drops.
Key opinions
- Subdomain Separation: Using separate subdomains for different email types (marketing vs. transactional) protects the primary domain's reputation.
- Gradual Volume Increase: Gradually increasing sending volume on the new subdomain helps build its reputation.
- IP Reputation Monitoring: Monitoring the IP address reputation of the new subdomain is important to prevent blacklisting.
- Engagement Impact: Low engagement rates negatively impact sender reputation and can cause Gmail reputation drops.
Key considerations
- Domain Protection: Implement strategies to shield the primary domain from deliverability issues on the new subdomain.
- Reputation Building: Focus on building a positive reputation for the new subdomain through consistent and engaging email practices.
- Blacklist Prevention: Take proactive steps to ensure the new subdomain's IP address remains off blacklists.
- Engagement Optimization: Optimize email content and sending practices to improve engagement rates and maintain a healthy sender reputation.
Expert view
Expert from Word to the Wise explains that a new subdomain's IP address can impact deliverability. He suggests carefully monitoring IP reputation during the transition phase and ensuring it's not blacklisted.
6 Mar 2024 - Word to the Wise
Expert view
Expert from Word to the Wise mentions focusing on engagement metrics, such as open rates and click-through rates, as these are important factors in determining deliverability. Low engagement can negatively impact sender reputation and cause Gmail reputation drops.
2 Nov 2023 - Word to the Wise
What the documentation says
5 technical articles
Technical documentation highlights the critical importance of proper email authentication (SPF, DKIM, DMARC) when migrating to a subdomain. Gmail requires these to be correctly set up. Maintaining a low spam rate (below 0.10%) as reported in Google Postmaster Tools is also essential. Microsoft recommends using SNDS to monitor IP health and joining JMRP. Implementing a strict DMARC policy (p=quarantine or p=reject) protects against spoofing. RFC documents define SPF syntax, and DKIM.org provides guidance on DKIM signing, emphasizing strong keys and valid signatures.
Key findings
- Authentication Required: SPF, DKIM, and DMARC are mandatory for good deliverability, especially with Gmail.
- Low Spam Rate: Maintain a spam rate below 0.10% to avoid Gmail reputation drops.
- IP Monitoring Tools: Utilize SNDS to monitor IP health and address deliverability issues.
- Strict DMARC Policy: Implement a DMARC policy with 'quarantine' or 'reject' to protect against spoofing.
- Valid DNS Records: Ensure sending domains or IPs have valid forward and reverse DNS records.
Key considerations
- Technical Expertise: Implementing these technical standards requires expertise in DNS records and email authentication protocols.
- Continuous Monitoring: Regularly monitor spam rates and authentication reports to identify and address issues promptly.
- DMARC Reporting: Pay attention to DMARC reports to identify and resolve authentication failures.
- Authorized Sending Sources: Ensure your SPF record accurately lists all authorized sending sources for your domain/subdomain.
- Key Strength: Use strong cryptographic keys when implementing DKIM signing.
Technical article
Documentation from DMARC.org explains the importance of implementing a DMARC policy with a 'p=quarantine' or 'p=reject' setting to protect your domain from email spoofing and phishing attacks. Monitor DMARC reports to identify and address any authentication issues.
27 Nov 2022 - DMARC.org
Technical article
Documentation from RFC explains proper SPF record syntax and usage to authorize sending servers. Ensure your SPF record is correctly configured to list all authorized sending sources for your domain/subdomain.
29 Mar 2025 - RFC
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