SonicWall error message - 554 No SMTPd here

Error Message

554 No SMTPd here

Emails are blocked by SonicWall with this error message.

The error means SonicWall considers one of Mail-List.com's IP addresses to have a flagged reputation (meaning the IP is potentially problematic).

How to Fix

In SonicWall, reputations are considered at the connection level. Add all Mail-List.com's IP Addresses as Trusted Connections.

Our IP addresses are listed on our website. Instructions are included for how to whitelist our servers.