Make Sure there is No Wireless Interference
Xbox One not connecting to WiFi problem can also arise if other wireless devices are interfering with the wireless network to which Xbox is connected. Wireless phones, microwave oven, ACs, speakers and many such devices interfere with the connection between the gaming console and the wireless router.
To fix this issue you need to improve the wi-fi signals. Try disconnecting other wireless devices and placing them far away from the router. You can also try to keep the router and Xbox One at a higher place.