Invalid License error for cPanel.
1. Check the validity of the license at http://verify.cpanel.net.
If it is valid:
2. Login to ssh.
3. Make sure that port 80 is open to contact cPanel license server and your server’s hostname is a FQDN (Fully Qualified Domain Name).
4. Stop the firewalls running in the server and run the below command.
This should update the correct license.
Go ahead playing with WHM!