Dealing with Email Blacklists
If your emails are being rejected by multiple providers, your server's IP address may have been added to an email blacklist. This guide explains what blacklists are, how to check your status, and how to get removed.
What is an Email Blacklist?
Email blacklists — also known as DNSBLs (DNS-based Blackhole Lists) or RBLs (Real-time Blackhole Lists) — are databases used by mail servers worldwide to identify IP addresses suspected of sending spam. If your server's IP appears on one of these lists, receiving mail servers will automatically refuse your emails.
Being blacklisted does not necessarily mean your server was intentionally sending spam. Common causes include a compromised user account, a vulnerable web application or script, misconfigured email authentication (PTR, SPF, DKIM), or a previous owner of the IP address having a poor sending history.
How to Check if Your IP is Blacklisted
Use a free online tool to check your server's IP against dozens of major blacklists at once. We recommend MXToolbox:
How to Get Delisted
If your IP is listed, you need to request removal from each blacklist individually. Before you do, it is critical to fix the underlying cause first.
Fix the root cause before requesting removal. If you submit a delisting request without resolving the underlying issue, your IP will be re-listed quickly — and repeated requests may result in a longer or permanent block. Common causes to investigate include a compromised user account, a vulnerable script or CMS plugin sending spam, or missing/incorrect PTR, SPF, or DKIM records.
Identify the blacklist — the MXToolbox report will tell you which specific list your IP is on and usually provides a direct link to their website.
Fix the root cause — resolve any compromised accounts, vulnerable scripts, or misconfigured DNS records before proceeding.
Visit the blacklist's website — each blacklist operates independently and has its own delisting procedure. Follow their instructions carefully.
Submit the removal request — once submitted, removal typically takes between a few hours and a couple of days depending on the blacklist.
Prevent Future Blacklistings
The best way to avoid blacklists is to maintain a clean sending environment. Key measures include:
Still having trouble?
If you have followed these steps and are still experiencing issues, our support team can help identify the root cause and assist with the delisting process.