How to enable spam filter in Plesk Control Panel ?

Solution :

[1] Login to your plesk control panel.
[2] Click on subscriptions >> subscription name
[3] Click on Mail
[4] Click on Mail Id
[5] Click on Spam Filter

Enable – Switch on spam filtering for this email address
What to do with messages classified as spam – Mark spam messages by adding the following text to message subject or Delete all spam messages
Spam filter sensitivity * – 5
Black List – You can mention the domain name one per line which you want to block
Trusted Languages – English
Click on ok