The intelligent spam protection is enabled by default in your hosting account. For its proper functioning you need to activate the SpamAssassin filter. If the SpamAssassin is disabled, you can re-enable it in cPanel » Spam Filters.
How does the intelligent SPAM protection work?
This "self-training" filter collects information from the incoming legitimate or unwanted emails you receive and the actions you take with them. Based on the gathered info, the tool starts to recognize and sort the messages you receive and it does it more efficiently every next time.
The filter recognizes the messages you sorted in the Spam and Junk folders as unwanted and protects your inbox from incoming spam messages in real time. For better outcome you need to move the unwanted emails into your Spam folder. Each time such messages are received they will be easily recognized and restricted from your incoming mail.
All other messages in the rest of the email account folders will be identified as ham. The term "ham" is synonymous for non-spam and is used to define legitimate mails. In case a ham email has been recognized as a spam message, you need to move it to another folder. This way you help the filter to start efficiently detecting unwanted mail and lower the probability of future mistakes.
If you have moved a message to the Spam / Junk folder by mistake, you can easily recover it by returning it to your inbox. The filter treats each email as unique so if it detects that a message has changed its location, the filter will modify its database information about that message.
The more messages you receive, the more effective the SPAM filter will become. This is due to the fact that the filter's system will acquire more data and examples for legitimate or unwanted emails.