How can I improve email deliverability and open rates for a client with a bad domain reputation, especially with Gmail, and what strategies should I use for unengaged users?
Matthew Whittaker
Co-founder & CTO, Suped
Published 4 Jun 2025
Updated 19 Aug 2025
8 min read
Improving email deliverability and open rates for a client with a compromised domain reputation, especially when facing issues with Gmail and a large segment of unengaged users, presents a significant challenge. It requires a strategic and methodical approach to rebuild trust with internet service providers (ISPs) and re-engage your audience effectively.
When a domain has a bad domain reputation in tools like Google Postmaster Tools, it indicates that mailbox providers, particularly Gmail, view your sending practices negatively. This often leads to emails landing in spam folders or being blocked entirely, severely impacting open rates. The underlying causes can vary, from poor list hygiene and unauthenticated sending to a sudden change in email volume or content.
We'll explore how to systematically address these issues, focusing on rebuilding domain reputation, optimizing email content and frequency, and implementing smart strategies for re-engaging users who haven't interacted with your emails in a while.
Diagnosing and understanding the reputation issue
A crucial first step is to thoroughly diagnose the current state of your domain's reputation. This involves checking your authentication records and monitoring your performance metrics. Proper email authentication protocols like SPF, DKIM, and DMARC are fundamental to proving your legitimacy as a sender. Without them, even well-intentioned emails can be flagged as suspicious.
Beyond authentication, actively monitoring your sender reputation is vital. Google Postmaster Tools (GPT) is a free, indispensable resource for any sender, especially if Gmail is a primary recipient. GPT provides insights into your domain and IP reputation, spam rates, feedback loops, and authentication errors, helping you pinpoint specific issues.
If you're on a shared IP address, it's important to understand that the sending practices of others on that IP can affect your deliverability. While some blocklists (or blacklists) might not directly impact Gmail, any listing on a significant blocklist is a red flag and should be addressed. Regularly checking various blocklists is part of comprehensive blocklist monitoring and crucial for maintaining a healthy sender reputation. You can also dive deeper into how email blacklists actually work to better understand their impact.
One common pitfall is attempting to send newsletters or marketing emails to an entire list, especially if it includes a significant portion of unengaged or dormant contacts. This can drastically worsen a bad reputation. Instead, focus on a controlled domain warming strategy by sending only to your most active subscribers first.
Strategies for rebuilding domain reputation
Rebuilding a poor domain reputation requires consistent effort and a focus on positive engagement signals. Start by drastically segmenting your list to identify your most engaged users. For a domain with a bad domain reputation, especially with Gmail and Yahoo, it's critical to send only to those who have recently opened or clicked your emails (e.g., in the last 30 days). This helps generate positive engagement signals, which are highly valued by mailbox providers.
Implement a strict list cleaning strategy. Regularly remove invalid or inactive email addresses. High bounce rates, especially hard bounces, signal poor list hygiene and can further damage your reputation. Consider using an email validation service to pre-clean your lists before sending. This prevents hitting spam traps, which are email addresses specifically designed to catch senders with bad list practices.
For ongoing reputation management, ensure your email content is relevant, engaging, and personalized. Generic, sales-heavy emails are more likely to be ignored or marked as spam. Focus on delivering value to your subscribers. If you've recently used a new subdomain for marketing, remember that a new domain warmingprocess takes time and requires a very slow, gradual increase in sending volume to build credibility. Sometimes, reverting to the original domain after warming is not as effective as sticking with the warmed domain if the warming process was not executed patiently enough.
Strategies for unengaged users
Dealing with unengaged users is a delicate balance. Continuing to send to them can signal to ISPs that your emails are not valued, negatively impacting your sender reputation. However, you also don't want to completely abandon potentially valuable contacts.
For those unengaged for 30 days or more, a different approach is necessary. Instead of regular marketing blasts, consider sending re-engagement campaigns. These emails should have clear, enticing subject lines and offer a compelling reason to re-engage, such as an exclusive offer, a survey to understand their preferences, or an update on new features they might find useful. Clearly state what they can expect by re-engaging.
If a user still doesn't engage after a dedicated re-engagement series, it's best to move them to a separate, less frequent communication list or suppress them from your main marketing sends. This practice protects your sender reputation by ensuring your high-volume sends are only directed to engaged subscribers, which improves overall email deliverability and open rates.
Audience segmentation
Continue to segment your list based on engagement, with separate campaigns for highly engaged versus less engaged users. This ensures you're sending the right message to the right audience, improving relevance and reducing complaints.
Content optimization
Focus on high-value, personalized content for engaged users. For unengaged users, craft compelling re-engagement messages designed to prompt a positive interaction, not just a sale.
Technical considerations and ongoing monitoring
Beyond list hygiene and content, several technical aspects contribute to improving your deliverability and open rates. Ensuring all your email authentication records are correctly set up and configured is paramount. This includes SPF, DKIM, and DMARC. For instance, a misconfigured DMARC record can lead to legitimate emails failing authentication checks, impacting your sender reputation.
Pay close attention to your email sending infrastructure. If you're using a shared IP, ensure your email service provider (ESP) has robust policies to prevent other users from negatively affecting your shared reputation. For a client with a severely damaged reputation, a dedicated IP might be considered in the long term, but it also requires a dedicated warming process and consistent sending volume to build its own reputation.
Regularly monitor your performance metrics. Track not only open rates but also click-through rates, complaint rates, and bounce rates. These metrics provide valuable insights into how mailbox providers perceive your emails and how your audience interacts with them. A high complaint rate, for example, is a strong negative signal that can quickly tank your domain's reputation. Addressing these issues systematically is key to improving overall deliverability.
Domain authentication status
Check SPF, DKIM, and DMARC records. Ensure they are correctly configured and aligned, which is crucial for proving email authenticity to Gmail and other mailbox providers.
Shared IP blacklists
While some blacklists (like Backscatterer and SORBS) might not directly impact Gmail deliverability, a presence on them suggests overall poor sending practices on the shared IP. It's advisable to address these listings with your ESP and consider a dedicated IP if issues persist.
Views from the trenches
Best practices
Maintain meticulous list hygiene, regularly removing unengaged subscribers and invalid addresses to improve sender reputation.
Segment your audience based on engagement levels and tailor your content to each segment for improved relevance.
Consistently monitor your domain reputation using Google Postmaster Tools for Gmail, and other similar services for other ISPs.
Prioritize email authentication protocols (SPF, DKIM, DMARC) to build trust with mailbox providers and ensure email authenticity.
Warm up new IPs or subdomains very slowly and deliberately to establish a positive sending history.
Common pitfalls
Sending to an entire list without segmenting, especially after a period of inactivity, which can drastically damage domain reputation.
Ignoring low open rates and high bounce rates, as these metrics signal poor engagement and can lead to blacklisting.
Assuming that being on certain blacklists (e.g., Backscatterer, SORBS) has no impact on overall deliverability.
Failing to implement or correctly configure email authentication, which makes emails appear suspicious to ISPs.
Not adjusting email content or frequency for unengaged users, leading to continued negative signals.
Expert tips
Focus on domain-specific issues, especially if open rates are significantly lower for one particular provider.
Re-evaluate your email content for unengaged users, asking questions like "Are you still looking?" or offering opt-down options.
For shared IP issues, contact your ESP to understand their policies and consider options for improving IP reputation.
If your client is using an ESP with poor support, consider its impact on addressing deliverability issues quickly.
Prioritize sending to recent openers and new sign-ups for a few weeks to positively impact your Gmail reputation.
Marketer view
Marketer from Email Geeks says they started with authentication, list cleaning, and warming a marketing subdomain. However, they are still struggling with sub-10% open rates for groups unengaged for over 30 days and experiencing spam placement issues, especially with Gmail.
2020-07-02 - Email Geeks
Marketer view
Marketer from Email Geeks says that new domains take significant time to warm, even after the initial warming phase. One client attempted to warm a new domain but ultimately returned to their original subdomain because the warming process was not slow enough to achieve effective inboxing.
2020-07-02 - Email Geeks
Sustained success in email deliverability
Improving email deliverability and open rates for a client with a bad domain reputation, particularly with Gmail, and for unengaged users, is a marathon, not a sprint. It demands patience, consistent monitoring, and a willingness to adapt your sending strategy. By prioritizing proper authentication, rigorous list hygiene, smart audience segmentation, and relevant content, you can gradually rebuild trust with mailbox providers and foster a more engaged subscriber base.
Remember, the goal is not just to send emails, but to ensure they reach the inbox and provide value to the recipient. This commitment to best practices will ultimately lead to improved deliverability and higher open rates, transforming a challenging situation into a successful email program. Continuously evaluate your performance and be prepared to iterate on your strategies as needed. For more insights on how to troubleshoot and improve low Gmail deliverability rates, consult additional resources.
Gmail, view your sending practices negatively. This often leads to emails landing in spam folders or being blocked entirely, severely impacting open rates. The underlying causes can vary, from poor list hygiene and unauthenticated sending to a sudden change in email volume or content.
Gmail and 
Yahoo, it's critical to send only to those who have recently opened or clicked your emails (e.g., in the last 30 days). This helps generate positive engagement signals, which are highly valued by mailbox providers.
