Email Blocklists: How to Check and Get Removed

How to check if you are on a blocklist

There are hundreds of blocklists in existence, but only a handful actually matter to your email deliverability.

Providers like Spamhaus, Spamcop, and Barracuda carry the most weight. If you are listed on one of these, major inbox providers will start bouncing your emails.

To check your status, you don't need to check each site individually. Use an aggregate tool:

1. Go to a free blocklist checker like MXToolBox.
2. Enter your sending domain (e.g., yourdomain.com).
3. Enter your sending IP address (you can find this in the headers of your emails, or ask your ESP).

If the tool shows green checkmarks across the board, blocklists are not your problem. If you see red marks next to major lists like Spamhaus or Spamcop, you have found the issue.

A warning about minor blocklists

Many aggregate tools will flag you on minor, obscure blocklists (like UCEPROTECT Level 3). Inbox providers largely ignore these minor lists. Do not panic or pay a removal fee to an obscure blocklist. Focus only on the tier-one lists.

Why did you get blocklisted?

Blocklists do not randomly target senders. If you are listed on a tier-one list, your domain or IP exhibited behavior that looks exactly like a spammer.

The three most common triggers are:

1. Hitting spam traps: You emailed addresses that exist solely to catch senders who scrape the web or buy lists.
2. High spam complaints: Too many real users clicked the "Mark as Spam" button on your recent campaigns.
3. Compromised accounts: Your email account or server was hacked and used to send outbound spam without your knowledge.

How to request blocklist removal (Delisting)

Getting removed from a blocklist is a straightforward process, provided you actually fix the underlying problem first.

Step 1: Stop sending

Do not attempt to push more mail through while you are listed. It will only increase your negative reputation. Pause all campaigns.

Step 2: Fix the root cause

If you don't fix the problem, you will be relisted within days of your removal.

• Ensure your email authentication (SPF, DKIM, DMARC) is set up correctly.
• Review your email list building and hygiene practices. Remove subscribers who haven't engaged in 90 days. Run your list through a verification tool.

Step 3: Submit the delisting request

Go directly to the website of the specific blocklist that flagged you (e.g., Spamhaus.org). Follow their specific removal process.

Most will ask you to fill out a short form explaining:

• How you collect your email addresses.
• Why you believe you were listed.
• What specific steps you have taken to ensure it won't happen again.

Be honest, concise, and professional. Blocklist operators are human. If you admit a mistake (e.g., "We sent a re-engagement campaign to a 3-year-old list without verifying it first") and show you have deleted the offending segment, they are much more likely to remove you.