Advanced Cloud Hosting/Renew Server SSL Certificate
When Parallels Plesk Panel control panel or another site is opened via HTTPS, a warning is displayed regarding an expired certificate.
How do you renew it?
There are no special Plesk certificates provided by Parallels. The default SSL certificate you used for the Parallels Plesk Panel is a self-signed certificate, which is generated once during the installation. The SSL certificate presence is required for SSL connections.
This is a default certificate shown in the server certificate repository at Server -> SSL Certificates