How to Check if Your Domain Is Blacklisted (and Get Delisted Fast)

Your email volume looks normal, but replies have dried up. Bounce messages mention "blocked" or "listed." There's a good chance your domain or sending IP has landed on an email blacklist — and the frustrating part is that nobody tells you when it happens. You just quietly stop reaching inboxes.

A blacklist (technically a DNSBL — DNS-based blocklist) is a database of domains and IPs known for sending spam. Mailbox providers consult these lists in real time and block or filter anything that matches. Getting on one is easy; getting off requires knowing exactly which list flagged you and why.

How domains end up blacklisted

• A spike in spam complaints from recipients
• Sending to spam traps (dead addresses planted to catch bad senders)
• A compromised account or server sending spam without your knowledge
• Sharing a poor-reputation IP on shared hosting or a cheap SMTP relay
• Sudden, unwarmed volume from a brand-new domain

The blacklists that actually matter

There are hundreds of blocklists, but only a handful carry enough weight to affect real delivery:

• Spamhaus (SBL, XBL, DBL) — the most influential by far; a listing here hurts immediately
• Spamcop — complaint-driven, widely consulted
• Barracuda — used by many corporate mail systems
• SORBS and UCEPROTECT — broader, more aggressive lists

How to check if you're listed

The fastest way is to run your domain through our free email deliverability checker, which checks your domain against the major blacklists alongside SPF, DKIM, and DMARC — no signup required. If anything is flagged, you'll see exactly which list it's on.

How to get delisted

Listings won't lift on their own until you fix the cause. The sequence:

• Find the root cause first. A compromised account, a bad mailing list, or broken authentication. If you request removal without fixing the cause, you'll be relisted within days.
• Clean it up. Secure accounts, remove invalid and unengaged addresses, and confirm SPF/DKIM/DMARC all pass.
• Submit a delisting request. Each blacklist has its own removal form (Spamhaus's is the most important). Be honest about what happened and what you changed.
• Wait and verify. Most lists clear within hours to a few days. Re-check to confirm you're off.

Don't get caught off guard again

The real cost of a blacklisting isn't the listing — it's the days or weeks before you notice. By then deals have gone cold and password-reset emails have failed. Zeqo Mail checks your domain against the major blacklists every single day and alerts you the moment you're listed, with the exact delisting steps. Pair that with good sending hygiene and you'll catch problems while they're still cheap to fix.