What Is an Email Blacklist? And How to Avoid It

December 7, 2023 by
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Many variables can affect your email marketing campaign, but one thing is certain: Getting your emails directly into your audience’s inbox is essential for successful communication. Yet, many businesses face a stumbling block: the risk of being blacklisted. This situation can make your emails go unseen, directly impacting your engagement and results. In this article, we’ll discuss what exactly an email blacklist is, how you can avoid it, and some other important tips. Let’s get straight to it!

Main Takeaways

  • Blacklists or blocklists are systems used to block spammy email domains.
  • Email blacklists can be maintained by internet service providers, blacklist operators, anti-spam organizations, email providers, and volunteer editors.
  • If you discover that your email domain is on a blacklist, you’ll need to address the root cause of the blacklisting and submit a de-list request to the blacklist operator.

What Is an Email Blacklist?

An email blacklist, also referred to as a blocklist, is a system used to combat spam by identifying and blocking spam senders. 

This process prevents these senders from delivering unsolicited content to recipients’ inboxes. Essentially, the blacklist contains a database of email addresses, domain names, and IP addresses recognized for distributing spam. Once a sender is added to this list, they are prevented from sending further emails or using contact forms to reach users. 

These blocklists are actively managed and updated in real-time to ensure effectiveness​​.

The primary purpose of email blacklists is to prevent the spread of unwanted spam content from untrustworthy sources. Since a significant portion of emails can be spam (for example, 48.63% in 2022), blacklists play a crucial role in keeping inboxes clear of such content​​.

How Does an Email Blacklist Affect You?

It goes without saying that you probably don’t want to be put on an email blacklist. Being on an email blacklist can have several negative impacts on your email communication and marketing efforts. Here are a few of the ways that being on a blacklist can negatively affect your business.

  • Emails Blocked or Sent to Spam: Your emails may be blocked or end up in spam folders, leading to low deliverability and engagement​​.
  • Decreased Sender Reputation: Being blacklisted can damage your reputation as a sender, affecting future email deliverability​​.
  • Reduced Trust and Reputation: Email providers might see you as a potential spammer, affecting your reputation even after removal from the blacklist​​.
  • Loss of Business Opportunities: Missing out on reaching your target audience can lead to lost revenue and decreased customer engagement​​.
  • Negative Impact on Email Marketing Campaigns: Blacklisting can cut off access to new leads and loyal customers, potentially reducing revenue​​.
  • Deliverability Rate Drop: Depending on which blacklist you’re on, your email deliverability rates can vary significantly​​.
  • Increased Bounce Rate: Emails may be rejected by recipients’ email servers, resulting in a higher bounce rate​​.
  • Difficulty in Removal from Blacklists: Once you are on a blacklist, it’s not an easy process to get removed. 
  • Legal Consequences: You may face legal issues for violating anti-spam laws and risk losing your email service provider or domain registrar​​.

Who Maintains the Blacklist?

Several entities maintain email blacklists, each with unique criteria and methods for listing and delisting email addresses, domains, or IP addresses. Here are the key players involved in maintaining these blacklists.

1. Internet Service Providers (ISPs)

Many ISPs have internal blacklists. They use these lists, along with algorithms and spam filters, to decide whether an email should be rejected, flagged as spam, or delivered to the recipient’s primary inbox. 

2. Blacklist Operators

There are also third-party blacklist operators that collect information about email senders. These operators manage blacklists that are used by a broad range of organizations and companies, including ISPs, mailbox providers, and anti-spam vendors​​.

3. Anti-Spam Organizations

These organizations create and maintain private email blacklists, which they provide as a service to larger entities like ISPs and mailbox providers. These lists are typically checked using inbox testing tools​​.

4. Email Providers

Companies like Google, Yahoo, and Outlook maintain their own email blacklists. These internal blacklists are part of their efforts to filter out spam and protect their users from malicious emails​​.

5. Volunteer Editors

The Spamhaus Block List (SBL) is a well-known blacklist managed by volunteer editors. These editors identify and list senders who trigger their spam trap networks, suggesting abusive or spammy behavior. An SBL listing can significantly impact your email deliverability due to its industry recognition and trustworthiness​​.

How Do You Get on Blacklists?

Avoiding email blacklists is key to running a successful campaign, but how do you get on these blacklists in the first place?

  1. Frequent Spam Flags: If many people mark your emails as spam, it can get you blacklisted. This often happens if your emails seem invasive.
  2. Outdated or Incorrect Email Addresses: Sending emails to wrong or old email addresses can also cause problems. 
  3. Delivery Troubles: Consistent problems in getting your emails delivered can alert email monitors, potentially leading to blacklisting.
  4. Sudden Changes in Email Activity: A big jump in the number of emails you send or unusual changes in your email patterns can set off alarms and lead to blacklisting.
  5. Compromised Email Accounts: If your account gets hacked and is used to send spam, it can lead to blacklisting.
  6. Email Spoofing: Faking the sender’s address in emails can get you blacklisted, as it’s a common spammer trick.
  7. Excessive Spam Complaints: If a lot of your emails are marked as spam or ignored, especially from recipients who didn’t opt in, it can lead to blacklisting.
  8. Spammy Email Content: Emails with spam-like subject lines, certain phrases like “Buy Now,” all caps, or unsolicited links and images can get you blacklisted. Some ISPs filter emails based on certain phrases like “money back guarantee” or “free,” which can lead to blacklisting.
  9. Violating CAN-SPAM Act: Not following rules like providing an opt-out option, using deceptive subject lines, and not respecting unsubscribe requests can impact your email deliverability and lead to blacklisting.
  10. Using Open Relay Servers: These servers let anyone send emails without authentication, and using them is a big security risk that can result in blacklisting.
  11. Rapid Email List Growth: If your mailing list grows too fast, it can alert ISPs and lead to suspicion and blacklisting.
  12. Sending to Bounced Addresses: Continually emailing addresses that bounce back can hurt your reputation and indicate spammy activity.
  13. Server Hacking: If your server is taken over for phishing attacks, it can lead to blacklisting. This is common for legitimate emails that end up blacklisted.
  14. Poor Email List Maintenance: Not cleaning your email list of inactive or duplicate addresses regularly can trigger spam alerts and lead to blacklisting. Failing to manage your email list properly, especially ignoring unsubscribe requests, can also lead to blacklisting.
  15. Emailing Unengaged Recipients: Continuously emailing people who don’t interact with your emails can harm your reputation and lead to blacklisting.
  16. Virus or Malware Infections: If your computer is infected, it can affect your emails and lead to your address being blacklisted.

How to Avoid an Email Blacklist

Here’s a guide to help you keep your email activities clean and reputable.

1. Only Email Subscribers

Stick to emailing contacts who have willingly subscribed to your emails. Avoid emailing contacts obtained from scraping websites, third-party sources, or purchased lists. Emailing people who haven’t subscribed to your emails is a surefire way to end up on a blacklist​​.

2. Clean Your Email Lists Regularly

Large email lists can do more harm than good if they include unengaged contacts. Regularly purge your email list of inactive addresses, as mailbox providers often convert inactive email addresses into recycled spam traps. Running re-engagement campaigns can help identify which contacts are still interested​​.

3. Avoid Manual Entry of Email Addresses

After events, instead of manually adding business card contacts to your database and mass emailing them, connect personally and guide them to subscribe to your list. This avoids the risk of sending emails to uninterested parties and reduces the chance of typing errors, which can lead to email bounces and lower deliverability​​.

4. Validate New Subscribers’ Email Addresses

Use email address verification tools to check the validity of email addresses collected through subscription forms. This step is crucial to avoid sending emails to non-existent addresses, which can harm your deliverability and risk blacklisting​​.

5. Don’t Spam

Avoid mass messaging, targeting the wrong audience, and sending low-quality content. Adhere to the CAN-SPAM Act’s principles, such as writing clear subject lines, making ads recognizable as ads, including contact information, allowing easy unsubscribe options, and honoring those requests​​.

6. Improve Email Deliverability

Use a separate domain for cold outreach, and consider setting up a paid Google Workspace account to improve your reputation. Ensure your email address receives messages, not just send them, to be seen as more reputable.

7. Implement Email Authentication Protocols

Utilize DKIM (DomainKeys Identified Mail), DMARC (Domain-based Message Authentication, Reporting, and Conformance), and SPF (Sender Policy Framework). These protocols verify the legitimacy of an email’s origin and ensure that only verified, non-malicious emails reach their destination, reducing the risk of being marked as spam​​.

8. Craft Relevant and Valuable Content

Understand your audience and provide them with valuable content. Keep your emails clear, concise, and personalized. Avoid using spammy language and excessive attachments or links.

9. Monitor and Adjust Email Sending Patterns

Be mindful of the volume and frequency of your emails. Gradually increase your email output and establish a consistent email schedule. Segment your audience and personalize your emails to enhance engagement and reduce the risk of spam complaints​​.

10. Use Reputable Email Service Providers (ESPs)

Partner with established ESPs like Mailchimp or SendGrid. They offer optimized email servers, well-managed IP addresses, and compliance with email standards. These ESPs also monitor and manage their sending IPs to ensure they remain off blacklists and provide tools to help you manage your campaigns effectively​​.

11. Regularly Monitor Your Email Reputation

Use tools like ReturnPath or SenderScore to monitor your email reputation. They provide analytics on spam complaints, bounce rates, and engagement levels, allowing you to make adjustments to your email strategy to maintain a healthy sender reputation and preempt blacklisting​​.

How to Check If You Are Blacklisted

Here are three ways to check if your email is blacklisted.

1. Use a Blacklist Checker Tool

An email blacklist checker is a software tool designed for a quick and easy check. You can use various online tools like MXToolBox, Barracuda Reputation Block List, MultiRBL, and SenderScore for this purpose. These tools aggregate data from multiple blacklists, providing a comprehensive check​​.

2. Check Specific Blacklist Sites

There are over a hundred email blacklists available, and some tools allow you to test your mail server’s IP address against these lists.

For example, the MXToolBox checks against over 100 DNS-based email blacklists.

3. DNS Checker Tool

This tool allows you to start scanning by clicking on “Check in Blacklists.” It retrieves the associated IP address and displays whether the domain, IP, or email is listed on any blacklists​​.

Using these methods, you can determine if your email is on a blacklist, which is crucial for ensuring the success of your email campaigns and communications.

What to Do If You Are on an Email Blacklist

Having your email domain blacklisted can be a drag! But don’t panic! If you find yourself on an email blacklist, there are specific steps you can take to address the situation. It’s important to act quickly and thoughtfully to rectify any issues and ensure your email communications remain effective. Here are the steps to take if your email is blacklisted.

1. Identify the Blacklist and Reason for Blacklisting 

Use tools like MxToolbox, DNSBL.info, or DNS Checker to determine which blacklist you’re on. Understand why your email was blacklisted, whether due to technical issues, compliance problems, or spam-like behavior​​​​.

2. Address the Root Cause

Before requesting delisting, resolve the issues that led to the blacklisting. This includes reviewing and improving your email-sending practices, content quality, email authentication, infrastructure, and recipient engagement. Ensure compliance with anti-spam regulations and monitor feedback loops from ISPs​​.

3. Submit a De-list Request to the Blacklist Operator

Provide detailed information about the corrective actions you’ve taken. Each blacklist has its unique delisting process, so follow the specific instructions provided by the blacklist operator. This may include submitting forms with your IP address, domain name, and a description of the steps taken to address the issue​​​​.

4. Be Clear and Honest in Your Request

In your delisting request, be straightforward and honest about the reasons for your blacklisting and the actions you’ve taken. Avoid making false claims or begging for removal.

5. Monitor and Follow Up

Keep track of your email deliverability after submitting your request. Be patient, as the delisting process can take time. Follow up with the blacklist operator if necessary but avoid sending multiple requests.

6. Implement Best Email Practices Going Forward

To prevent future blacklisting, maintain good email practices. This includes regularly cleaning your email lists, ensuring your content is relevant and valuable, and adhering to anti-spam regulations.

The Timeframe for Email Blacklist Removal

It can take time to get your email off a blocklist. The exact timeframe depends on the reason for initially being put on the blacklist. Minor issues might resolve automatically in a few weeks, while serious issues, like sending spam, take longer. Each blacklist has different rules. 

Some may process your request in a matter of hours, others in days or more. First-timers usually get quicker help, but repeat offenses could lead to a permanent ban. Automated removal happens for small issues, but big problems need a manual request.

Fixing the root cause of your blacklisting is key for faster removal. Patience and following the blacklist’s guidelines are important during this process.

Don’t Get Blacklisted!

A staggering 347.3 billion emails are sent and received daily in 2023, a number expected to reach 392.5 billion by 2026. 

Knowing why emails get blacklisted and who’s behind these lists is crucial for developing strategies to stay off them. Keep your lists clean and follow anti-spam rules, and you should steer clear of blocklists. If you are blacklisted, simply identify the list, address the issue, and follow the delisting process.



About The Author

Mike Yon

Mike is the Co-Owner of Growth List.

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