If your server is under NAT and doesn't have any public network interface, the Panel has to be activated by using a license key after the installation. In order to do that you need to:
1. Open the panel billing account
2. Select a license that is directed to the public IP-address of your server.
3. Copy an activation key.
4. Paste the activation key into the license activation window in your control panel installation.
How does the activation key works?
The activation key is created automatically when a license is ordered. You can get your activation key by double-clicking a Key icon of a corresponding license.
The activation key can be used once. In case the license is required to be activated again - it is required to generate a new key as well. A new key can be generated only once in a month in your billing account or it can be requested via Technical Support.
Note: to activate a license with a key - the license server has to be available from the server where the Panel is installed. To check the license server availability you may run the following command on the server where the Panel is installed:
mogwai licence ping-server