If you get repeated spam from any particular email address, such as a mailing list you cannot unsubscribe from, you can blacklist that domain.
Step 1: Click the ‘Spam Filters’ link on the main cPanel dashboard
Step 2: Toggle the ‘Additional Configurations (for Advanced Users)’.expand the list by clicking the “Show Additional Configurations” link.
Step 3: Click the ‘Edit Spam Blacklist Settings’ Link.
Step 4: Add a New Blacklist From Item (blacklist_from)
When configuring the blacklist_from setting, you are allowed to use wildcards such as “*” and “?”. For example:
firstname.lastname@example.org — Blacklists a single specified email address
*@example.com — Blacklists all of the email addresses at example.com
?email@example.com — Blacklists a single character in the email address. So in this example, firstname.lastname@example.org would be allowed, but email@example.com would not.
Once you have entered your Blacklists_from item, you can either add more or click the “Update Blacklist (blacklist_from)” button