For LOS (Loss of Signal) red lights on fiber or advanced gateways, it usually means the incoming optical line is not detected or has low signal. Double-check that the fiber line is connected properly and that there's no bend or physical damage. When it's green and steady, everything is fine. However, when it blinks red or stays solid red, it signifies a Loss of Signal, a problem preventing your router from communicating. Router status lights, often referred to as LED indicators, are small lights on the front panel of your router. A red light or light (or if the light. The tables in this article provide detailed information about the possible appearances of the LED lights on each device, the possible causes of each state, and what you should do.