What to do when a domain for email addresses in your database is being shut down?
Michael Ko
Co-founder & CEO, Suped
Published 18 May 2025
Updated 18 Aug 2025
6 min read
Discovering that a domain for email addresses in your database is being shut down can feel like a sudden blow to your email marketing efforts. It means a portion of your hard-earned subscriber list could become invalid overnight, leading to deliverability issues and potentially impacting your sender reputation.
When a domain ceases to exist, emails sent to addresses on that domain will bounce. These aren't just soft bounces, which might be temporary delivery issues, but hard bounces, indicating a permanent failure. Too many hard bounces can signal to mailbox providers that your list is outdated or poorly managed, negatively affecting your overall domain reputation and potentially landing your emails on a blocklist (or blacklist).
The key is to be proactive. Waiting until the domain is completely offline and your emails start bouncing is a reactive approach that can harm your deliverability. Instead, I focus on identifying the issue early and taking steps to mitigate the damage before it impacts our email program.
Understanding the impact and detection
The first step is always to identify which domains in your database are affected. This might come from news alerts, direct communications from the domain owner, or, in some cases, by observing a sudden increase in hard bounces from specific domains. When a domain no longer exists, emails sent to it are typically returned by the sending server because there's nothing to receive them, as highlighted in discussions about what happens to old email addresses.
Ignoring these signals or failing to remove defunct email addresses from your list can have serious consequences. Each hard bounce counts against your sender reputation, and a consistently high bounce rate can lead to your emails being flagged as spam, even if your content is legitimate. This is a critical aspect of email deliverability issues.
The risks of ignoring defunct domains
Increased bounce rates: Sending to non-existent email addresses directly contributes to hard bounces, damaging your sender reputation.
Blocklist (or blacklist) placement: High bounce rates can trigger blocklist (or blacklist) listings, preventing your emails from reaching other legitimate inboxes.
Wasted resources: Each email sent to an invalid address costs you money and impacts your engagement metrics negatively.
To effectively manage this, you need a plan. It involves segmenting your audience, communicating clearly, and adapting your list hygiene practices. This situation also highlights the broader issue of email database decay and the need for regular cleaning, a topic extensively discussed in resources like what to do about email database decay.
Proactive communication and list management
Once you've identified the affected domains, your priority should be to communicate with those subscribers. The goal is to encourage them to update their email addresses with a new one that isn't tied to the disappearing domain. This requires a well-thought-out re-engagement campaign.
Consider sending a series of emails with a clear, concise message. Explain the situation transparently and provide a straightforward way for them to update their contact information. Offering a small incentive can also help increase response rates.
Crafting your re-engagement email
Subject line: Make it clear and urgent, for example, 'Important: Action Required for Your Email Subscription'.
Body content: Briefly explain the domain shutdown and its impact on their subscription. Provide a link to a form where they can update their email address easily.
Call to action: Clearly state what you want them to do and why it's beneficial for them to do it now.
As the shutdown date approaches, I recommend sending a final communication to any remaining subscribers on the affected domains. This message should serve as a last reminder that you will no longer be able to reach them via their old email address. It's a professional courtesy and helps manage expectations.
On the day before the domain is officially decommissioned, it's best practice to segment out and remove all remaining email addresses associated with that domain from your active mailing lists. This prevents any further hard bounces and protects your sender reputation from unnecessary damage. You can manage this with a simple segment rule in your email service provider (ESP):
Example segmentation ruleSQL
Email Domain CONTAINS "olddomain.com"
Mitigating deliverability risks and list health
Preventing bounces is far more effective than simply waiting for your ESP to handle them. While most ESPs will automatically unsubscribe hard bounces, accumulating these bounces, even temporarily, can negatively impact your email deliverability and potentially lead to account reviews. My preference is always to be proactive, as it safeguards your sender reputation more effectively.
Proactive unsubscription
Maintains sender reputation: By removing addresses before they bounce, you avoid penalties from mailbox providers and blocklists (or blacklists).
Improves user experience: Subscribers receive relevant communications, fostering trust and engagement.
Cost efficiency: Avoids paying for attempted sends that are guaranteed to fail, saving resources.
Relying on ESP auto-unsubscribe
Temporary deliverability impact: Even if bounces are automatically handled, the initial bounce spikes can still harm your sender reputation.
Delayed resolution: Your list remains unclean for a period, potentially attracting spam traps or further deliverability issues.
Potential for account flags: Consistent high bounce rates can lead to closer scrutiny from your ESP, possibly resulting in account suspension.
Domain shutdowns, while impactful, are also a stark reminder of the importance of ongoing email list hygiene. Regularly cleaning your email database to remove invalid, inactive, or unengaged subscribers is a fundamental best practice for strong email deliverability.
Domain expiration and its impact
ICANN (Internet Corporation for Assigned Names and Numbers) sets the rules for domain name registration. If a domain expires and isn't renewed, it eventually becomes available for re-registration by someone else. When a domain is rested or closed, all associated email services will cease. If you own the domain, you should contact your registrar immediately to discuss options to restore it, as detailed by Namecheapin their knowledgebase. This is different from a domain being intentionally shut down by a provider, but the impact on email addresses is similar.
Long-term list hygiene and strategy
Beyond addressing an immediate domain shutdown, I recommend implementing regular list validation processes. This involves using tools or services that can verify the validity of email addresses on your list, helping you identify and remove invalid ones before they cause hard bounces. This continuous effort is vital for maintaining a healthy email marketing program.
Issue Type
Description
Impact on Deliverability
Hard bounces
Permanent delivery failures, often due to non-existent addresses (e.g., domain shutdown).
Significantly harms sender reputation and can lead to blocklisting.
Soft bounces
Temporary delivery issues (e.g., mailbox full, server down), as explained by Mailer Daemon guides.
Less severe, but frequent occurrences can still indicate issues or lead to hard bounces.
Spam traps
Email addresses specifically designed to catch spammers. Often, these are old, defunct, or purchased addresses.
Hitting these leads to immediate blocklisting and severe damage to reputation.
It's also important to have a strategy for transitioning email sending domains or subdomains when necessary. This preparedness ensures that even unexpected changes, like a major domain shutdown, can be handled smoothly without compromising your deliverability.
Views from the trenches
Best practices
Proactively communicate with subscribers on affected domains to collect new email addresses.
Segment your list and remove all contacts with the affected domain before the shutdown date.
Prioritize preventing bounces by preemptive unsubscription over relying on ESP automatic handling.
Regularly clean your email lists to remove old, invalid, or unengaged email addresses.
Monitor news and announcements from large email providers for potential domain changes or shutdowns.
Common pitfalls
Waiting for hard bounces to occur before removing affected email addresses from your list.
Failing to communicate transparently with affected subscribers about the upcoming domain shutdown.
Not having a clear process for re-engaging or unsubscribing users from defunct domains.
Ignoring signs of email database decay, leading to higher bounce rates and poorer sender reputation.
Assuming your ESP's automatic bounce handling is sufficient protection against deliverability issues.
Expert tips
Establish a routine for monitoring your email list health and identifying potential issues early.
Develop a playbook for handling domain-related changes or shutdowns to ensure a consistent response.
Educate your team on the importance of list hygiene and its direct impact on email deliverability.
Utilize email validation services to proactively identify invalid email addresses.
Regularly review your email metrics, particularly bounce rates, to catch anomalies quickly.
Marketer view
Marketer from Email Geeks says they would send communications to subscribers asking them to re-opt-in with a new address, send a final mail before the end-of-life date, and unsubscribe those contacts to prevent sending.
2024-07-30 - Email Geeks
Marketer view
Marketer from Email Geeks suggests that most ESPs will unsubscribe hard bounces automatically, implying one might just email them normally.
2024-07-30 - Email Geeks
Maintaining a healthy email ecosystem
Facing a domain shutdown in your email database can be daunting, but with a proactive and strategic approach, you can minimize its impact on your email program. The core principles revolve around early detection, clear communication with affected subscribers, and meticulous list hygiene.
By actively managing these situations, you not only preserve your sender reputation but also ensure that your email list remains vibrant and effective. It's an opportunity to strengthen your relationship with subscribers and reinforce the health of your overall email ecosystem, crucial for avoiding issues like being on a blacklist (or blocklist).
ICANN (Internet Corporation for Assigned Names and Numbers) sets the rules for domain name registration. If a domain expires and isn't renewed, it eventually becomes available for re-registration by someone else. When a domain is rested or closed, all associated email services will cease. If you own the domain, you should contact your registrar immediately to discuss options to restore it, as detailed by 
Namecheapin their knowledgebase. This is different from a domain being intentionally shut down by a provider, but the impact on email addresses is similar.
