Quote

Unplug the power cable from the back of the router, modem, or gateway for 5 minutes. If you have a router and a modem, unplug the power cable from both devices.

Restart your console. Press and hold the Xbox button in the center of your controller to open the Power Centre. Select Restart console and then select Restart. (If the console appears to be frozen, press and hold the Xbox button on the console for 10 seconds, until the console turns off. After the console shuts down, touch the Xbox button on the console again to restart.)

After 5 minutes, plug the modem or gateway in first, and wait for all the lights to return to their normal state.

If you are using a router, plug in the router and wait for all the lights to return to their normal state.