You receive an error similar to the following when you attempt to update your license:
The license cannot be updated because the cPanel license servers are not accessible from within this sever:
Could not reach port 23 on auth.cpanel.net from this server -- connections may be throttled.
Could not reach port 2089 on auth.cpanel.net from this server -- connections may be throttled.
This typically occurs whenever you cannot reach auth.cpanel.net from your server.
Please unblock or allow connections, on port 2089 to auth.cpanel.net, from within your server. The cPanel licensing system tries to connect to auth.cpanel.net to validate the cPanel license. If it cannot establish a connection on its primary port 2089, it will attempt to connect through other popular service ports such as the following: