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. That blinking red LOS light means your router has lost its connection to your internet provider's network. Before you panic or call tech support, there are several simple fixes you can try at home that often solve this problem in minutes. Sometimes it may be due to a problem with your internet service provider, although you could also be experiencing this issue due to improper configuration of your router, a poorly connected cable, etc.
