For business based websites and other websites, auto-reply is an important thing to get recurring visitors, with Plesk you can set auto-reply messages. To enable auto-reply follow the below steps.
Login to your Plesk panel.
Go to Mail tab.
Select Email Addresses
Select the email address and click on Auto-Reply icon.
Now select "Switch on auto-reply" check box and specify the required details. Once you are done, click OK to complete.