To do this first you must use a PC that is connected to the same network as your Xbox One to discover its physical address and then copy it over to your Xbox console.
How to fix the Additional Authentication Needed error If you are on WiFi at home, or even hard wired, go back into the network settings and tell the Xbox to use Dhcp and you will be fine. A MAC address is something permanently associated with the hardware and cannot be changed. MAC address will be listed next to 'Wireless MAC' on the right hand side of the screen (this is also where the IP address and other information is located) 5. To find the MAC address on your Xbox One follow these simple steps: 1. Write down the 12-digit address for the one that you are using (wired or wireless.)In your router, you will need to assign this MAC address to the IP address you have chosen (see step 2 for instructions.).
Press ▲ or ▼ to highlight Manual Setup, then press OK.