If the LOS light on your fiber router or ONT is blinking red, it usually means Loss Of Signal. This guide explains the likely causes, the checks you can do at home, and when the issue needs technician support. 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. A red light on your router can be a source of frustration and confusion. Depending on the brand of router, the red light can mean a few different things, but for the most part, it indicates an issue connecting to the internet. 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.
[PDF Version]