Email & SMTP · 1 min read
Blacklisted Domain or IP: Remove from Blocklists and Restore Delivery
What's happening
Your emails are being blocked because something in them, such as your sending domain, sending IP or a URL in the message, is listed on a public blocklist (RBL or DBL). A typical bounce reads: "Email blocked due to listed URLs or IPs/domains on public blacklists."
Key facts
- Blocklists are third-party databases of suspicious IPs, domains and URLs. Gmail, Outlook and Yahoo check several of them.
- A listing can affect every email you send, not only one campaign.
- Removal often takes 24–72 hours after the cause is fixed. Some lists delist automatically after a period of good sending.
Common lists include Spamhaus (SBL, DBL), Barracuda, SURBL, URIBL and SpamCop.
Fix it step by step
- Find the listing. Run your domain and every domain linked in your email through a blocklist checker (for example MXToolbox).
- Check your links. Remove link shorteners and any URL that's listed. One bad link can block the whole email.
- Stop the cause. Pause campaigns to old or purchased lists, remove hard bounces and complainers, and check for compromised forms that are adding spam sign-ups.
- Request removal. Use each blocklist's delisting form. Explain what you fixed.
- Restart slowly. Send to your most engaged contacts first, then gradually increase volume.
Prevent it
- Use confirmed opt-in on your forms.
- Clean your list regularly with email validation.
- Authenticate your domain with SPF, DKIM and DMARC.
- Watch your bounce and complaint rates in your email statistics.