Check your sending IP is not on any email blacklists

15 min Impact: medium Effort: low ✓ Manual completion

Your sending IP reputation is tracked separately from your domain reputation, and a blacklisted sending IP causes real deliverability problems, legitimate email landing in spam or being rejected outright, regardless of how well your domain-level authentication is configured.

Shared hosting or shared email sending infrastructure means your IP reputation can be affected by other users on the same infrastructure, worth checking directly rather than assuming it is fine.

How to do it

1

Identify your actual sending IP

Check your email service provider settings, or the headers of a test email you send to yourself.
2

Check it against major IP blacklists

A dedicated blacklist checking tool covers dozens of lists at once.
3

If listed, investigate the real cause

Could be your own sending practices, or on shared infrastructure, another user entirely.
4

Request delisting once the cause is resolved

Each blacklist has its own removal request process.

Common mistakes

On shared hosting or shared email infrastructure, your sending IP reputation can be damaged by someone else's bad behavior entirely outside your control, worth confirming with your provider if this happens repeatedly.

How you will know it is done

Your sending IP checks clean across major blacklist services.

Tools that help

MX Toolbox Blacklist Check ↗

Checks IP reputation across many blacklists at once.

Track this in your hive

The Security Ring turns this into a real, permanent mission — mark it complete once you have genuinely done it.

Open this mission in H.I.V.E. →