Add Trusted IP on cPanel greylisting
When greylisting mode activated, we can’t simply whitelist it. We have to add into trusted host from greylisting user interface first. This can be accessed through WHM as root user.
Accessing Greylisting
This can be accessed through Home > Email > Greylisting. Or simply when accessing WHM panel, use search function on top left and type greylisting.
Add IP into Trusted Host
When greylisting is enabled, a simple whitelist can’t be done. This can be done by adding IP into trusted host. See below image.

Now add it the single IP or range IP and don’t forget to fill comment section which ticket it refer to. So other engineer able to trace it.
