In order to be able to verify your licenses, the appliance will need access to a hostname on the internet: https://licensing.nomadesk.com.
Make sure it can be accessed from the appliance.
If it's not accessible, you will see error messages like: 'Unable to download your license from the licensing server.'
In order to make it accessible, sometimes you will need a firewall exception, or if you have a proxy, here's how you can set it up:
Create a file:
with the contents (modify to your own settings of course):
proxy_host = 'proxy.example.com'
proxy_port = 8080
proxy_login = 'username'
proxy_password = 'password'
If no authentication is needed, you can leave the login and password values empty.
Once this has been set up, you will connect to the license server through the proxy.