Right after the installation, Plesk uses a trial license key. To get a paid license key, go to the Plesk online store (shop.plesk.com), select, and then purchase a necessary license key.
Once you purchase the key, you will receive an activation email with your activation code.
- Go to Tools & Settings > License Management (under "Plesk") and click Install Key.
- Enter the code you received in the email to the "Enter an activation code" field and click OK.