Mail Tab in Plesk Admin Panel
Plesk allows users to select some basic email settings for their domains. Disabling email is not possible on this tab - for that, you will need to adjust the Resources tab or disable it by modifying the domain's parameters later on. Because we selected an option to allow changing mail settings in a subscription on the Permissions tab, anything we set here is considered a default and will not be enforced.
This is where you can select which webmail client a subscription uses, and the ones that are available depend on what is currently installed on the system. By default, the only option for Windows Shared Hosting and those on a Windows Dedicated prior to July 2019 is the SmarterMail Web Client. Those on new Windows Dedicated Servers starting July 2019 will have MailEnable by default. It is possible to add an external webmail client to Plesk.
Enable mailing lists
Policy on mail for non-existent users
Each subscription can define its own policy on how mail that is not addressed to an existing email account should be handled. The "Bounce with message" option will direct the mail server to reject the email with a message. The "Forward to address" option allows all email to be forwarded to another address, which may be useful for setting up a "catch-all" email address. The "Reject" option simply rejects the mail out-of-hand with no reason given to the connected client, which is the most secure option and the one that should be chosen as the default.