Plesk License Error: The license key is invalid. In order to use Plesk, please obtain and install a new valid license key.

Symptoms

• The following error appear in Plesk:

Error: The license key is invalid. In order to use Plesk, please obtain and install a new valid license key. Your current license is not valid because it is already activated on another Plesk server. The Plesk EULA (https://www.plesk.com/legal/) prohibits the use of a single license on two or more servers at the same time. To continue using Plesk, either install a new license or install your current license once again by entering its activation code. It was sent to you by email when you purchased the license. Cannot find the activation code? You can retrieve it using Plesk 360. To do so, log in to https://platform360.io/ with the email you used to purchase the license, go to the "Licenses" tab, and see your license's activation code. Or you can contact Plesk Licensing and Purchase support using the online form (https://www.plesk.com/licensing-and-purchase-support/). Remember to mention your license number in the "How can we help you?" section of the form.

Cause

Implemented anti-piracy mechanism assigns Plesk license to the latest server where the license was installed using activation code. There are the following reasons for the error to appear

• any hardware changes
• previous license multiuse, that means your license was at some point activated on 2 Plesk instances at the same time, which is against Plesk Terms and Conditions

Resolution

To resolve the issue, please reinstall your license in Plesk using its activation code. Please note: license retrieve will not work, a reinstallation is required.