The following warning is displayed in Plesk:
CONFIG_TEXT: 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.
System time is incorrect.
On the same page where the warning is shown, check the Key expiration date :
- If the Key expiration date is in the future, check the system time by running the date command in the Linux shell or date /T in the Windows command line. If it is incorrect, change it to the correct one.
- If the Key expiration date is in the past, it means that the key is, indeed, expired. Check this article for further troubleshooting: