A Domain Name System Blacklist (DNSBL) is a list that allows internet service providers and administrators to block emails from systems known for sending spam.
Why might your domain be blacklisted?
Usually caused by degradation in domain reputation — most often from sending emails classified as spam-like.
How to improve your reputation:
- Add an SPF Record
- Add a DKIM Record
- Test emails using mail-tester.com
- Send emails only via authenticated SMTP over SSL/TLS
How to delist your domain:
Once you’ve fixed the root cause, visit the blacklist provider’s site and follow their removal process. There are two types:
- Self-Service Removal – You can remove the listing manually
- Time-Based Removal – Lower-level listings are automatically removed after 1–2 weeks