How to Check if your Domain is Blacklisted?

Your emails hit spam. Open rates drop. Replies slow down.
The cause? Your domain might be blacklisted.
If you send cold emails, your domain must stay clean.
A blacklisted domain kills deliverability. It ruins sender reputation. It breaks trust.
The worst part? Most teams don’t notice the blacklist until damage hits.
Here’s how to check fast and fix it if you are blacklisted.
Blacklisted: What It Means
Blacklisted means spam filters or security tools flagged your domain or IP for bad signals, too many bounces, spammy words, or weak replies. Once flagged, your emails get blocked or hit spam, killing reach and sinking your campaign.
To run cold outreach right, you must stay off blacklists. A flagged domain hurts deliverability, ruins your sender reputation, and breaks trust with prospects. Avoid this by sending responsibly: keep bounce rates low, warm up your inbox, and set clean, verified DNS records. It’s much easier to prevent damage than to fix it.
Signs You Might Be Blacklisted
Here are the red flags to watch out for.
- Sudden drop in open or reply rates
- Bounce rates suddenly spike
- Emails continuously land in spam folders
- Emails never reach inboxes
- Even transactional or one-on-one emails don’t go through
Use These Tools to Check Blacklists Quickly
To reach the inbox, your cold emails need a clean sender record. That means checking often if your domain or IP is blacklisted. Use tools like MXToolbox, MultiRBL, Talos Intelligence, or Debouncer, which scan many blacklists in seconds and show where you’re listed. Quick checks catch problems early, fix deliverability fast, and protect your reputation before your outreach stalls.
Mailpool keeps your domain monitored across major blacklists so your emails stay deliverable and your reputation stays strong. By detecting blacklist appearances in real time, Mailpool helps you take immediate action before they affect your campaigns.
What to Do If You’re Blacklisted
Identify the Root Cause
Getting delisted without fixing the issue leads to repeat blacklisting. Look for:
- High bounce rates
Check the quality of your lead list. Make sure that all the emails are verified.
- Spammy content
Check your email content. If the email includes words like “Free,” “Buy now,” “Act fast,” or “Guaranteed”. Filters link these to scams or aggressive marketing, so they flag them quickly.
- Unverified DNS settings
Verify if your DNS records are misconfigured or missing critical entries.
- Low engagement
Low open or reply rates tell spam filters your emails aren’t wanted, raising your risk of getting blacklisted.
- Sudden volume spikes
If you start sending too many emails too quickly, especially without gradually warming up your inbox. It can trigger spam filters and get your domain blacklisted.
- Run a deliverability audit to find what caused the block.
Submit a Removal Request
Each blacklist has its own removal procedure. Some are automated, others require manual appeal. Here are examples:
Spamhaus
Visit Spamhaus Blocklist Removal Center, enter your IP/domain, and follow their instructions.
Barracuda
Submit a delisting request through the Barracuda Removal Form.
SORBS
Create an account, then submit a ticket.
UCEPROTECT
You may need to wait for auto-removal.
Most blacklists require:
- A valid explanation
- Proof that the issue is fixed
- A working postmaster or abuse email (e.g., postmaster@yourdomain.com)
Monitor & Prevent Future Listings
After removal, don’t fall back into the routine. Stay proactive to keep off blacklists. Build a strong sending setup: set SPF, DKIM, and DMARC right to prove domain trust. Warm your inbox slowly before sending more. Watch bounce rates, spam hits, and how users engage. Clean your list often to skip bad addresses. Send only to people who might reply. A solid setup and smart habits protect your sender name and keep your emails out of spam.
Avoid Getting Blacklisted at All Costs
In cold email outreach, staying off blacklists isn't just a technical checkbox. It’s the foundation of long-term deliverability and sender reputation. Once your domain or IP gets listed, your emails may never reach the inbox, no matter how compelling your message is. Proactively monitoring blacklists, maintaining proper authentication records, and practicing responsible sending behavior help safeguard your outreach efforts. Think of blacklist prevention as an investment: a small effort now that protects every email you send moving forward.
Avoiding blacklists is key to landing in the inbox and running effective outreach. Mailpool handles the automated monitoring for blacklists and spam alerts so you can fix issues before they hurt deliverability. Let Mailpool protect your domain while you focus on results.