Why Is My Domain Blacklisted? Causes and How to Get Delisted
Your domain gets “blacklisted” when a DNS blacklist (DNSBL) sees spam-like behaviour from the IP addresses your mail and site use — most often a compromised mailbox or server sending spam, a misconfigured open relay, a poor sending reputation, or a shared/cloud IP where a neighbour was flagged. The listing is almost always about the IP, not the domain name itself.
What “blacklisted” actually means
Inbox providers consult DNSBLs — lists like Spamhaus, SpamCop and Barracuda — to decide whether to accept, spam-folder or reject a message. When people say their domain is blacklisted, what’s usually listed is the IP behind its A record (the web server) or its MX records (the mail servers). Some lists also track domains found in spam (URI/domain blacklists), but IP listings are what break most email.
The common causes
- A compromised account or server. A cracked mailbox password or an exploited web app starts sending spam from your IP — the fastest route onto a list.
- An open relay or misconfigured mail server that lets anyone send through it.
- Reputation and complaints. Recipients marking your mail as spam, or sending to stale lists that hit spam traps, drags your reputation down. Google and Yahoo both expect a spam-complaint rate under 0.3% (Google, Yahoo).
- Shared or cloud IPs. On shared hosting or a cloud provider, a neighbour’s bad behaviour can list a range you happen to sit in.
- Aggressive/collateral lists. Some lists flag entire ASNs or netblocks. These are noisy and low-value — a listing there rarely reflects anything you did.
How to find out which list — and why
Look up your domain’s A and MX IPs against the major DNSBLs. Our free blacklist check does this across 52 lists in one pass and separates them by severity: an authoritative listing (Spamhaus, SpamCop, Barracuda, CBL) is a real deliverability problem; advisory/collateral listings are shown separately so they don’t send you chasing false alarms.
Each list publishes why it lists an IP and how to check — Spamhaus, for instance, gives a lookup and a reason for every listing.
How to get delisted
- Fix the root cause first. Delisting before you stop the spam just gets you re-listed. Secure the account, patch the app, close the relay.
- Request removal on each list that flags you. Most authoritative lists have a self-service removal form; some auto-expire once the behaviour stops.
- Warm back up by sending clean, wanted, authenticated mail. Reputation recovers with good behaviour over time.
Stay off in the first place
Publish and pass SPF, DKIM and DMARC so providers can tell your mail from a spoof, keep your lists clean, and monitor your IPs so you hear about a listing within hours — not when your open rates collapse. You can verify your setup with our free SPF, DKIM and DMARC checkers, or watch it continuously with blacklist monitoring.
Sources
- Spamhaus (lookups and listing reasons): https://www.spamhaus.org/
- Google — Email sender guidelines (spam-rate threshold): https://support.google.com/a/answer/81126
- Yahoo — Sender Best Practices: https://senders.yahooinc.com/best-practices/