Plesk with SmarterMail installed shows the following error when trying to create a Mailing List in Plesk > Subscriptions > example.com > Mail button > Mailing List > Create:
The email address of the mailing list administrator should be registered on the same domain as the mailing list.
Bug #PPPM-3927. It is fixed in Plesk Onyx.
Upgrade to the latest Plesk version.
If upgrade is not possible:
Create the Mailing List from Plesk > Subscriptions > example.com > Mail tab instead of Mail button in domain's settings.
If this workaround did not help, try to upload patch.
Unpack .zip archive and place
MailList.php file into