You have connected your device to your InvizBox 2 however it is showing up as "Not Connected" on the Devices page in the Administration Interface.
How the InvizBox 2 checks device connectivity
This is a known behaviour for some devices when they are connected to the InvizBox 2. The InvizBox 2 uses the "ping" command to check if a device is connected to it or not. The way this works is the InvizBox 2 sends a message to the connected device that has an active DHCP lease, and if the device replies it is shown as connected in the Administration Interface. The reason for this is that having a lease is not enough to determine if devices are in fact still connected as the lease stays active even if the device disconnects.
Certain devices, for example devices that use Windows, have the reply to the "ping" command disabled by default and will not appear as "Connected" on the InvizBox 2. For some other devices their reply to this command will depend on the mode that they are in, for example Apple devices in "Stealth Mode" will not respond to the ping command.
What can you do?
If your device is not showing up as "Connected" make sure that it has the ability to respond to the "ping" command. You may need to search online on how you can check and enable this on your particular device.
Even though your device is not showing up as "Connected" in the InvizBox 2's Administration Interface it is still protected and functionality like site and device blocking will still affect this device.