You probably just need to reconnect te printer to your router.
Check that your router has a 'WPS' button. (Almost all modern routers do). Turn your printer on. Press the 'Wireless' button on your router, holding it in for at least 3 seconds, until a light starts flashing. Go to your router and press the 'WPS' button. (You might need to hold it in a short while.). A light on your router should start flashing and then, when the connection has been made, the light on your printer should cease flashing.