How can I fix spam trap issues related to disposable email domains and low open rates?
Michael Ko
Co-founder & CEO, Suped
Published 31 Jul 2025
Updated 18 Aug 2025
8 min read
Dealing with spam trap issues and low open rates can feel like navigating a maze blindfolded. You see high delivery rates, but the engagement just isn't there. This often points to deeper problems within your email list, particularly the presence of disposable email domains.
Disposable email addresses, often used for one-time sign-ups or to avoid spam, can seriously harm your sender reputation. When you send to these addresses, many of which turn into spam traps, you're essentially signaling to mailbox providers that your list hygiene is poor or that you're engaged in questionable sending practices. This perception can lead to your legitimate emails being routed to the spam folder, drastically lowering your open rates.
The challenge is that these addresses are designed to be temporary, so even if they appear valid initially, they quickly become inactive or transform into active spam traps. If a significant portion of your list is comprised of these, your deliverability will suffer, impacting your overall email marketing effectiveness.
Resolving these issues requires a multi-faceted approach, focusing on prevention, ongoing list maintenance, and robust authentication. By understanding the root causes and implementing strategic fixes, you can significantly improve your inbox placement and boost those elusive open rates.
Understanding the problem
Spam traps are a critical component of email deliverability. They are email addresses used by internet service providers (ISPs) and anti-spam organizations to identify senders of unsolicited email. These addresses are not used by real people and therefore should never receive legitimate mail. When an email is sent to a spam trap, it immediately signals that the sender's list acquisition methods are flawed or that their list is outdated, possibly obtained from questionable sources.
Disposable email domains, such as mailsac.com or temp-mail.org, provide temporary email addresses that expire after a short period. People use them to sign up for services without revealing their primary email address. The problem for senders is that these addresses quickly become inactive or are repurposed as spam traps. Sending to a high volume of these addresses can lead to your IP or domain being added to a blacklist (or blocklist), severely impacting your sender reputation.
A direct consequence of hitting spam traps or sending to disposable domains is a drop in your email open rates. ISPs use engagement metrics, including open rates, to determine your sender reputation. If your emails consistently go unopened, or worse, are marked as spam because of spam trap hits, mailbox providers like Google or Outlook will start filtering your messages into the spam folder, or even reject them entirely. This creates a vicious cycle where low engagement further harms your reputation.
Types of spam traps
Pristine spam traps: These are addresses created solely to catch spammers and have never been used for any legitimate purpose. They are often published publicly on websites to entice bots. Any email sent to these is a clear indicator of poor list acquisition, such as scraping or purchasing lists.
Recycled spam traps: These were once valid email addresses that have become dormant or abandoned. After a period of inactivity (e.g., six months to a year), ISPs repurpose them as spam traps. Hitting these indicates a lack of regular list hygiene, as you're sending to inactive contacts.
Understanding these types is key to addressing the issue effectively. For more details, you can explore how to identify email spam traps.
Preventing disposable email domains and spam traps
The most effective way to fix spam trap issues and improve open rates is to prevent disposable email addresses from entering your list in the first place. This starts with robust list acquisition practices. Always use permission-based list building, where subscribers explicitly opt-in to receive your emails. Double opt-in is highly recommended, as it verifies the email address and ensures the subscriber's genuine interest.
Implement email validation at the point of signup. Many email validation services can detect disposable email domains, as well as invalid or risky addresses, in real-time. By blocking these addresses before they even reach your database, you can significantly reduce your exposure to spam traps and maintain a cleaner, more engaged list. This proactive approach is crucial for maintaining a strong sender reputation.
Regularly cleaning your email list is just as important as initial validation. This involves identifying and removing inactive subscribers, hard bounces, and any addresses that haven't engaged with your emails in a long time. These stale addresses are prime candidates for becoming recycled spam traps. Automating this process helps ensure your list remains healthy and full of engaged recipients. Strategies for effective list cleaning are critical for improving overall email deliverability.
Proactive measures
Double opt-in: Require subscribers to confirm their subscription via email.
Real-time validation: Use an email validation service at signup forms.
Captcha: Implement on signup forms to deter bots and automated submissions.
Reactive measures
Regular list cleaning: Periodically remove inactive or unengaged subscribers.
Segmenting: Isolate high-risk or low-engagement segments for specific handling.
Bounce management: Automatically remove hard bounces to prevent further damage.
Improving open rates and sender reputation
Low open rates are often a symptom of underlying deliverability issues, including spam trap hits. Beyond list hygiene, improving open rates directly relates to your sender reputation, which is influenced by email authentication. Ensure your domain is properly authenticated with SPF, DKIM, and DMARC. These protocols prove that your emails are legitimate and prevent spoofing, building trust with mailbox providers. This foundational setup is critical for email deliverability.
Content quality also plays a significant role. Irrelevant or poorly structured content, overuse of spam trigger words, and poor formatting can all lead to emails being flagged by spam filters. Focus on providing value, personalizing your messages, and crafting compelling subject lines. Remember, engaging content keeps subscribers active, which in turn boosts open rates and positively impacts your sender reputation.
Sender reputation is a score that ISPs assign to email senders to gauge their trustworthiness. A low score means your emails are more likely to land in spam. Maintaining a high sender reputation involves consistent positive engagement, low bounce rates, and minimal spam complaints. Regularly review your email sending practices and segment your audience to send targeted content. This helps avoid sending to disengaged users, which can lower your overall open rates and impact your domain's standing.
Regularly monitoring your email deliverability metrics is essential. Pay close attention to your bounce rates, particularly hard bounces, as these can indicate invalid or non-existent email addresses. A sudden spike in bounce rates, especially for specific domains, could signal a spam trap hit. Also, track your spam complaint rates and unsubscribe rates. High numbers here suggest that your content isn't relevant or that your sending frequency is too high.
Actively checking if your domain or IP is listed on any email blacklists (or blocklists) is crucial for a healthy sender reputation. Many public blocklists exist, and a listing can significantly hinder your emails from reaching the inbox. Tools that provide blocklist monitoring can alert you immediately if you get listed, allowing you to take swift action to request removal. This proactive monitoring helps in recovering your domain reputation.
If you discover you've hit spam traps or your open rates are consistently low, don't panic. First, immediately remove any identified disposable or problematic email addresses from your list. Then, segment your list, focusing on your most engaged subscribers to send emails to initially. This helps rebuild your sender reputation by demonstrating positive engagement to ISPs. Over time, you can gradually re-engage less active segments with targeted campaigns. Recovering from a damaged reputation is possible, but it requires patience and consistent effort.
DNS authentication protocols
Proper configuration of your DNS records is fundamental to email deliverability. These records verify your sender identity and help prevent spoofing, which directly impacts your inbox placement and open rates.
SPF (Sender Policy Framework): Specifies which mail servers are authorized to send email on behalf of your domain. It helps prevent spammers from sending messages that appear to come from your domain.
DKIM (DomainKeys Identified Mail): Adds a digital signature to your outgoing emails. This signature verifies that the email has not been tampered with in transit and that it genuinely originates from your domain.
DMARC (Domain-based Message Authentication, Reporting & Conformance): Builds upon SPF and DKIM, telling receiving servers what to do with emails that fail authentication (e.g., quarantine, reject, or allow). It also provides valuable reports on email authentication failures. You can use DMARC monitoring to get insights into your email ecosystem.
Always validate email addresses at the point of capture, using real-time validation services to detect disposable domains.
Implement a double opt-in process for all new subscribers to ensure their email addresses are valid and they genuinely want to receive your emails.
Segment your email list based on engagement levels, and regularly remove inactive or unengaged subscribers to avoid recycled spam traps.
Monitor your sender reputation metrics, including bounce rates, spam complaints, and open rates, using tools like Google Postmaster Tools.
Maintain clear and concise email content, avoiding spam trigger words and consistently providing value to your subscribers to boost engagement.
Common pitfalls
Purchasing or using rented email lists, which are often riddled with spam traps and invalid addresses.
Failing to implement real-time email validation at signup forms, allowing disposable addresses into your database.
Neglecting to regularly clean your email list, leading to a build-up of inactive contacts that can become recycled spam traps.
Ignoring low open rates and high bounce rates, which are key indicators of underlying deliverability issues.
Not properly authenticating your emails with SPF, DKIM, and DMARC, making your messages appear suspicious to ISPs.
Expert tips
If you have a large list with many disposable emails, consider quarantining that segment and attempting re-engagement with highly targeted, low-volume sends.
Educate your team on the importance of email list hygiene and the dangers of sending to unvalidated addresses to prevent future issues.
For very high volumes of disposable emails, consider if your lead generation methods need adjustment, as it suggests an issue with lead quality.
Analyze engagement patterns specific to different email clients and domains to pinpoint where deliverability issues are most pronounced.
Consider gradually re-warming your sending IPs after extensive list cleaning to rebuild a positive sending history with ISPs.
Marketer view
Marketer from Email Geeks says that having 5,000 disposable email addresses from a single domain like mailsac.com on a list is far too many and indicates a serious problem.
2023-03-02 - Email Geeks
Expert view
Expert from Email Geeks says that zero percent or one hundred percent open rates often suggest a configuration issue with open tracking, and seed testing should be considered.
2023-03-01 - Email Geeks
Taking control of your email deliverability
Fixing spam trap issues and addressing low open rates is a continuous process that hinges on maintaining a healthy, engaged email list and ensuring proper email authentication. By diligently preventing disposable email addresses from entering your system, regularly cleaning your list, and actively monitoring your sender reputation, you can significantly improve your email deliverability.
Remember, every email sent to a valid, engaged recipient strengthens your sender reputation, while every email sent to a spam trap or an inactive address erodes it. Prioritize quality over quantity, and your efforts will be rewarded with better inbox placement and higher engagement.
Google or 
Outlook will start filtering your messages into the spam folder, or even reject them entirely. This creates a vicious cycle where low engagement further harms your reputation.
