Plesk comes with a trial license key, which is automatically installed to the control panel. This license key allows you to create one user account, host one web site and one mail box. Therefore, to fully use the Plesk control panel as you need, you should obtain a license key from SWsoft, Inc. or one of its resellers and install it to the control panel.
The license key is automatically updated every six months regardless of your Software Update Service subscription term. To allow proper license handling, be sure to leave the port 5224 open.