Plesk is a Webhosting software . which is installed on a windows machine
Plesk needs to do a automatic renewal but it fails to do at times :
The license key is invalid. In order to use the Parallels Plesk Panel, please obtain and install a new functioning license key. Your license key has expired. To continue using your Parallels Plesk Panel you must purchase a non-expiring commercial license key.
Just Press “Retrieve Keys”
And click ok
Log out and login back