1. First login into your website's Plesk Control Panel.
2. Now click on the 'Mail' tab of your control panel. This will make the Mail tab visible in your browser.
3. In the Mail tab, you will find a list of all the email addresses present for your domain.
4. Click on the desired email address to switch on antivirus protection.
5. This will open email settings for the selected email account. In the email settings click the "Antivirus" tab to switch on antivirus protection.
6. Then tick the check-box " Switch on antivirus protection for this e-mail address " there. This will enable antivirus protection for that address.
7. Now choose the desired mail scanning mode. You can switch on scanning for “only incoming mail”, “only outgoing mail”, or “incoming and outgoing mail”.
8. Now click the 'Ok' button to complete the setup