What Are Email Blacklists (Blocklists) and How to Get Off One

Few things can hurt your email marketing more than ending up on a blacklist. Or as some in the industry now call it, a blocklist. Both words mean the same thing: your domain or IP has been flagged as suspicious, and mailbox providers no longer trust your emails.

If you’ve noticed a sudden drop in open rates or your campaigns are bouncing at unusually high levels, there’s a good chance you’re on a blacklist. The good news however, is that email blacklist removal is possible. But first, you need to understand how these lists work.

What Is an Email Blacklist (Blocklist)?

An email blacklist is essentially a filter. It is a list of IP addresses or domains that have been identified as sending spam or unwanted messages. Mailbox providers like Gmail, Outlook, and Yahoo use these lists to protect their users.

There are two main kinds of email blacklist:

1. IP-based blacklists – These track the reputation of sending IPs. If your server is marked, all emails from that IP are blocked.
2. Domain-based blacklists – These track the actual sending domain. If your domain is listed, inboxes and mail providers stop trusting your messages.

While experts often prefer the term “blocklist,” most marketers and everyday users still search for “email blacklist” when trying to figure out why their campaigns aren’t being delivered.

How Do You End Up on a Blacklist?

Nobody gets listed by chance. There is always a reason. Here are the most common ones:

• Too many spam complaints from recipients.
• Poor list hygiene, such as sending to spam traps or old, invalid addresses.
• Sending a large volume of email from a brand-new IP without warming it up.
• Misleading subject lines or content that looks spammy.
• Using purchased or scraped email lists.

In short, blacklists are usually a symptom of bad list practices. Which is why strong email list hygiene best practices are so important.

How to Know If You’re Blacklisted

If you’re wondering, “Am I on an email blacklist?” The answer is easy to find.

• Use tools like MXToolbox, Spamhaus, or MultiRBL to check your domain or IP.
• Monitor your deliverability metrics. A sudden drop in inbox placement is often a red flag.
• Check your bounce logs. If you see error codes mentioning “blacklist” or “blocklist,” you’ve found the issue.

Step by Step Email Blacklist Removal: 

Being blacklisted can be frustrating, but here's a checklist on how to get back on the white list: 

1. Find out why. High complaints or spam traps are usually the cause.
2. Fix the issue. Clean your database, improve your list hygiene, remove bounces, and stop sending to questionable addresses.
3. Review the blacklist policy. List operators often have terms for removal on their documentations. Some operators auto-remove from the blacklist after a period, while others require a formal request to be made before removal. 
4. Request removal. Contact the list operator. Explain what went wrong and what you’ve done to fix it.
5. Stay clean. Monitor bounce rates, keep your list healthy, and ensure your email authentication is set up correctly.

How to Avoid Blacklists in the First Place

The best email blacklist removal strategy is not needing one. Prevention is everything. Here's a few steps to follow to keep your reputation strong and your emails in the recipient inboxes. 

• Authenticate your email with SPF, DKIM, and DMARC.
• Warm up new IPs slowly before sending at scale.
• Clean your list regularly with email database cleaning.
• Send relevant content your subscribers actually want.
• Make unsubscribing simple so people don’t hit the spam button.

Final Thoughts

It doesn't matter what you call it, a blacklist or a blocklist; the meaning is the same: trouble for your deliverability. However, it’s not permanent. With the right steps, email blacklist removal is achievable, and better yet, you can avoid landing on one in the future.

Keep your lists clean, authenticate your email, and always send content people want to receive. Do that, and you’ll be fine.