The product license expired. The following errors may occur:
You are currently operating within the grace period of your product license.
Error: The license key is invalid. In order to use the Plesk, please obtain and install a new functioning license key.
Your license key has expired. To continue using your Plesk you must purchase a non-expiring commercial license key.
There are several reasons for the issue to occur.
Check if your license renewal invoice has been paid
If you are using a lease license, please make sure your license renewal payment was successfull and license was renewed for the next month. Refer to the following article for more details:
213386729 My license is in grace period, as it was not renewed. What do I do now?
Check if your server can connect Odin license server
If your lease license renewal has been successfully paid or you are using retail ('Purchased') license, please make sure outgoing connection to the license server is allowed. For more information, see article:
213383529 License fails to update
Check if the system time is correct on server
213950825 Expired license warning in Plesk
If none of the above solutions helped, check the following article:
213373589 License key automatically terminated [Troubleshooting]