1. Enter SPAM Expert dashboard via client area. If user is not familiar with this then may refer to the below guideline: (How To Enter SPAM Expert Dashboard) Please click here. 2. Once enter, click on "Sender Blocklist " button under "Allowlist/Blocklist " session.3. Key in the email address or hostname that you with to blocklist in the Sender box. 4. Click on "Add" to allowlist the email address / hostname.