How to recover email deliverability and reputation after failed warm-up and poor sending practices?
Matthew Whittaker
Co-founder & CTO, Suped
Published 23 Jun 2025
Updated 18 Aug 2025
7 min read
It is disheartening when you put effort into warming up a new domain and IP, only to see your emails land in spam, or worse, find your IP on a blocklist. I have experienced this frustration, especially when a past accidental large send or consistently poor sending practices have already damaged the sending reputation. Recovering from such a setback can feel like an uphill battle, but it is achievable with a strategic and patient approach.
Often, the challenge stems from a combination of overly aggressive warm-up schedules and a failure to address underlying issues from previous sending habits. Even with a new domain or IP, the negative patterns can follow you. Let us explore the steps to diagnose what went wrong and how to systematically rebuild your email deliverability and sender reputation.
Diagnosing the problem
When your deliverability takes a hit after a warm-up, the first step is to accurately diagnose the problem. A common pitfall is ramping up email volume too quickly, especially on a new IP or domain. Internet Service Providers (ISPs) view sudden spikes in volume with suspicion, as this is a tactic often used by spammers. I also frequently see issues arising from sending to disengaged lists or lists acquired without proper consent, which leads to high complaint rates.
Another major factor can be inherited reputation from previous sending domains or IPs. If your organization previously had poor sending practices, switching to a new domain without correcting those underlying issues often means the problems will persist. This is particularly true if the new domain is a subdomain of a previously struggling top-level domain. Even a shared IP that was already on a blacklist (or blocklist) can severely impede your efforts from the start.
Monitoring your sender reputation is crucial for identifying these issues early. Tools like Google Postmaster Tools provide invaluable insights into your domain and IP reputation, spam rates, and delivery errors for Gmail recipients. Regularly checking these metrics can help pinpoint specific areas of concern. For other providers, observing open rates, click-through rates, and bounce rates across your campaigns can reveal where deliverability issues are most prevalent.
Symptoms of a failed warm-up or poor sending practices
Spam folder placement: Emails consistently landing in the spam or junk folder instead of the inbox.
Low open rates: A significant drop in how many recipients open your emails, even to engaged segments.
High bounce rates: An increase in hard or soft bounces, indicating issues with email addresses or recipient servers.
Blocklisting: Your IP or domain appearing on public or private email blocklists (blacklists).
Recipient complaints: An uptick in users marking your emails as spam or unsubscribing at higher rates.
Immediate actions for recovery
Once you have identified that your email deliverability and reputation are suffering, the immediate response needs to be decisive. The first step is to significantly reduce your sending volume, or even pause non-essential campaigns. This gives your domain and IP a chance to recover from a bad reputation by minimizing further negative signals. Continuing to send large volumes to unengaged recipients will only exacerbate the issue.
Next, turn your attention to your email list. High bounce rates and spam complaints are often a direct result of poor list hygiene. Clean your list rigorously, removing any invalid, inactive, or unengaged addresses. Focus your immediate sends on your most engaged segment, people who have recently opened or clicked your emails. This positive engagement helps rebuild trust with ISPs. Consider implementing a double opt-in process for all new sign-ups to ensure you are only sending to genuinely interested recipients.
It is also critical to verify your email authentication records: SPF, DKIM, and DMARC. Incorrect or missing records can significantly impact deliverability, as ISPs use these to verify your sending legitimacy. Ensure your DMARC record is properly configured, as Gmail and Yahoo's new sender requirements place a strong emphasis on these protocols. Simultaneously, check if your dedicated or shared IP is on any major blocklists (blacklists) using a blocklist checker. If listed, follow the delisting procedures, which often require demonstrating improved sending practices.
Rebuilding your sender reputation
Rebuilding sender reputation after a failed warm-up or poor practices requires a long-term commitment to best practices. Your approach to email warm-up needs to be much slower and more deliberate than simply doubling volume daily. Focus on sending to your most engaged subscribers first, gradually expanding to broader segments as your reputation improves. Monitor engagement closely and adjust volume based on positive signals.
Content relevance and quality are paramount. Ensure your emails provide value, are well-designed, and avoid spam-triggering words or formatting. Encourage positive engagement, like replies and moving emails from promotions to the primary inbox. If you are migrating sending domains, proactively inform your subscribers about the change through your existing, better-performing channels. This sets expectations and encourages them to look for your emails from the new domain.
Consistency in sending volume and frequency is also important. Avoid sudden spikes or drops that can trigger ISP filters. Instead of aggressive daily increases, aim for a steady, measured growth. This patient approach teaches ISPs that you are a legitimate sender with consistent sending habits. Remember, reputation is built over time through positive interactions, so focusing on genuine engagement is key to sustainable deliverability.
Old warm-up strategy
Rapid volume increase: Doubling or tripling send volumes daily, irrespective of engagement.
Broad audience targeting: Sending to the entire list from day one, including unengaged or risky contacts.
Ignoring engagement: Focusing solely on volume progression without analyzing inbox placement or user interactions.
Modern warm-up strategy
Gradual, engagement-based increase: Slowly raising volume based on positive recipient feedback.
Hyper-segmentation: Starting with the most active and engaged users, then gradually expanding.
Continuous monitoring: Daily analysis of deliverability metrics, adjusting strategy in real-time.
Ongoing monitoring and prevention
For ongoing health and to prevent future reputation issues, robust monitoring and a proactive approach are indispensable. Continuously track key deliverability metrics like bounce rates, spam complaint rates, and inbox placement across major ISPs. Utilize tools that provide detailed insights into your sending performance, identifying potential problems before they escalate. Consistent monitoring allows you to react swiftly to any dips in deliverability.
Automate list hygiene processes to regularly remove invalid or unengaged subscribers. This reduces the risk of hitting spam traps or generating excessive bounces, which are major reputation killers. Regularly review your email content for anything that might trigger spam filters, such as excessive images, broken links, or suspicious keywords. Adherence to email regulations like CAN-SPAM, GDPR, and similar local laws is not just good practice, it is mandatory.
Finally, cultivate a culture of deliverability awareness within your team. Ensure everyone involved in email marketing understands the importance of sender reputation and their role in maintaining it. By combining vigilance with best practices, you can safeguard your email program and ensure your messages consistently reach the inbox.
Views from the trenches
Best practices
Start with very low sending volumes to your most engaged audience when warming a new domain or IP.
Implement double opt-in for all new subscribers to ensure high-quality, consenting leads.
Regularly clean your email lists to remove inactive, invalid, or unengaged contacts, especially if you had poor sending practices previously.
Monitor your domain and IP reputation daily using available tools like Google Postmaster Tools for proactive insights.
Common pitfalls
Aggressively increasing send volume during warm-up, trying to rush the process and causing damage.
Sending to an entire email list, especially a cold or unengaged one, resulting in high complaints and bounces.
Failing to address the root causes of poor sending practices before attempting a new warm-up.
Ignoring email authentication (SPF, DKIM, DMARC) or having misconfigured records, leading to failed verification.
Expert tips
Engagement is king. Focus on sending highly relevant content that prompts opens, clicks, and replies to signal positive intent to ISPs.
A gradual, curated warm-up strategy reacting to daily engagement is far more effective than an arbitrary volume-doubling schedule.
If mail consistently lands in spam, reduce volume and reassess your audience quality and content before resuming full sends.
Even if your top-level domain has a good reputation, a problematic subdomain or shared IP can still cause significant deliverability issues.
Marketer view
Marketer from Email Geeks says they started a new domain/IP warm-up with Gmail emails, increasing volume daily, but experienced a reputation drop after day 5. They noted their shared IP was on a blocklist and their dedicated IP was bad, despite warming up over eight domains successfully in the past.
2025-04-29 - Email Geeks
Expert view
Expert from Email Geeks says that getting a new domain or IP to evade reputation problems is typically not a good idea if underlying practices remain unchanged. Problems tend to follow, and it's essential to understand if the audience genuinely wants the emails, how recent their engagement is, and if they opted in specifically for the type of offers being sent.
2025-04-29 - Email Geeks
The path forward
Recovering email deliverability and reputation after a failed warm-up or poor sending practices is a journey that demands patience, meticulous attention to detail, and a fundamental shift in strategy. It is not about quick fixes or simply changing domains, but about committing to an ongoing process of optimizing your sending behavior and respecting your recipients' inboxes. By implementing robust authentication, cleaning your lists, adopting a slow and engagement-driven warm-up, and continuously monitoring your performance, you can steadily rebuild your sender reputation.
Remember, ISPs prioritize positive user engagement. Every email you send should be genuinely desired by the recipient, providing value and encouraging interaction. This commitment to quality and relevance is the cornerstone of sustainable email deliverability and long-term success. While the path to recovery can be challenging, a consistent and data-driven approach will ultimately lead to improved inbox placement and a healthier email program.
