Email blacklist (also called DNSBL/RBL) is a database that flags sender domains or IP addresses suspected of spam or risky practices. When a sender is listed, mailbox providers may filter, junk, or block messages, which reduces inbox placement and reach.
Why it matters. If you’re blacklisted, even legitimate campaigns can vanish into spam. Common triggers include high bounces, spam complaints, poor list hygiene, missing authentication (SPF, DKIM, DMARC), or sudden spikes in sending.
- Symptoms: sudden drop in opens, rise in bounces/blocks, more complaints.
- Quick check: run a DNSBL lookup and review recent campaign metrics.
- Next step: fix the root cause (list quality, consent, authentication) and request delisting where applicable.
Learn more in the full guide: Email Blacklist — How to Check, Remove, and Prevent.
For step-by-step lookups, see How to Verify an Email Blacklist.
Note: Mailpro helps with sender authentication and list hygiene to prevent listings and keep deliverability healthy.
Mailpro and email blacklists
Listed before you notice, rotated before it hurts
Mailpro monitors every major email blacklist and rotates sending IPs the moment something lists — your campaign keeps delivering while we resolve the listing in the background.