BoxTrapper wants all email senders who are not on the whitelist to reply a verification email before you receive mail. This avoids your inbox from spam.
You want to get the hint of undesirable emails then you enable this on all your emails or only on selected emails and you need to configure BoxTrapper.
1. Login to your cPanel Account,
2. In the “Email” section, click on “BoxTrapper” Icon.
3. Under the BoxTrapper Page, see a list of emails Beneath the “Account” tab and the status of BoxTrapper (enabled/disabled) Beneath “Status” tab. Press on the “Manage” Link.
On the BoxTrapper Manage Page, if the current status is “Disabled”, then click on the “Enable” button.