SSL certificate used by Parallels Plesk Panel has expired. How can it be renewed ?

Symptoms:
When open Parallels Plesk Panel control panel or any site via HTTPS the waring about expired certificate is shown.

How to renew it?

Resolution:
There are no any special Plesk certificates provided by Parallels.
The default SSL certificate you used by Parallels Plesk Panel is a self-signed certificate which is generated one time during Plesk installation. SSL certificate presence is required for SSL connections.

This is default certificate shown in server certificate repository at Server -> Certificates (for Parallels Plesk Panel 7.5, 8.x) and at Settings -> SSL Certificates (for Parallels Plesk Panel 9.x).

You can create your own self-signed certificate at page Certificates or purchase real certificate from one of the world certificate authorities.
To create new self-signed SSL certificate login to Parallels Plesk Panel as administrator, change to page Certificates and create new certificate.

For Parallels Plesk Panel version 7.x, 8.x:

Server -> Certificates -> Add New Certificate

For Parallels Plesk Panel version 9.x:

Settings -> SSL Certificates -> Add SSL Certificate

Fill in required preferences and click button {Self-Signed}

New self-signed SSL certificate will be created in server certificate repository.

To assign this SSL certificate for securing your Parallels Plesk Panel mark enabled new SSL certificate in the list and push Secure control panel if you have Plesk 8.2 or later, or Install if you have older Plesk version.
Also, see Plesk documentation how to setup self-signed certificates.

After you created or uploaded new certificate into Plesk and wish to use it for domains you should set it for every IP you need, so domains use it when you access them via HTTPS. It can be done on page Server -> IP Addresses -> "choose IP" by selecting needed Certificate in "SSL Certificate" drop down menu.