Your Product Key specifies a maximum number of nodes that you may connect to the UTM-1 appliance.
The UTM-1 appliance tracks the cumulative number of nodes on the internal network that have communicated through the firewall. When the UTM-1 appliance encounters an IP address that exceeds the licensed node limit, the My Computers page displays a warning message and marks nodes over the node limit in red. These nodes will not be able to access the Internet through the UTM-1 appliance, but will be protected. The Event Log page also warns you that you have exceeded the node limit.
To upgrade your UTM-1 appliance to support more nodes, purchase a new Product Key. Contact your reseller for upgrade information.
Your have not installed your product key. For further information, see Upgrading Your Software Product.