How to Block Email Address/Domain via Cpanel Spam Filters (SpamAssasins)
Login to your Cpanel: http://domain.com/cpanel *(domain.com is to be replaced with your actual domain)

Under Email section, click on Spam Filters

Click to expand Show Additional Configuration

Click Edit Spam Blacklist Settings and click on Add a new "blacklist_from" Item to add blocked domain or email address

You can add blocked domain or email address in the following format
Blocking the whole domain: *@domain.com
Blocking a single email address: spammer@domain.com


Under Email section, click on Spam Filters

Click to expand Show Additional Configuration

Click Edit Spam Blacklist Settings and click on Add a new "blacklist_from" Item to add blocked domain or email address

You can add blocked domain or email address in the following format
Blocking the whole domain: *@domain.com
Blocking a single email address: spammer@domain.com

Updated on: 04/08/2021
Thank you!