Finding the hostname of the mail server
This article describes how to find out the name of the mail server you should use for Plesk Hosting. This is useful when setting up a mail client, a mail program on your site, or other utilities.
This only applies to the Hosting service. It does not apply to the Email Box service.
Steps
Login to your account and click the Domain Names tab
Click on the domain name in question
Click on Manage Advanced Domain Record Settings
In the table, find the MX record and in the Record field enter the name of the mail server