Nintendo Wii Us are only able to get internet access over a wired connection and are unable to connect over a wireless connection. Since the Wii U does not come with an ethernet port built in, you will have to purchase a wired LAN adapter compatible with the Wii U. Before trying to register, make sure you have an ethernet cord connecting your Wii U to the Data port in your room.
To register your Wii U, you need to find the MAC Address of your Wii U and manually register it after you connect the adapter to the Wii U. To find the MAC Address, follow these steps:
1. On your Wii U GamePad, go to the Wii U Menu and select System Setting.
2. Choose the option Internet.
2. Select View MAC Address
3. The MAC Address you want to enter is the LAN Adapter MAC Address.
LAN Adapter MAC of 00-00-00-00-00-00
If you get an all 0 MAC address, try these steps to get it connected:
1. Plug the LAN adapter into a computer running Windows. Windows will then install the drivers for the adapter automatically.
2. Connect to the internet through the LAN adapter (make sure another ethernet cable isn't plugged in and that you aren't connected to the wireless).
3. Open your browser and register like you would a computer (make sure you put Wii U as the device description).
4. Plug the LAN adapter back into the Wii U and run a Connection Test.
5. It should now be connected.