The Linksys router red light indicates a problem, usually one with hardware or connectivity. It may occur due to a lost internet connection or incorrect configuration. Make sure all of the cables are firmly attached by first inspecting them. To resolve short-term issues, restart your router and modem. If the problem persists, try a factory reset or updating the router's firmware. For professional assistance in fixing the problem, get in touch with Linksys WiFi Customer Support or use the Linksys app.