A green light usually means normal operation, while red or blinking lights signal issues. If you see a “LOS” (Loss of Signal) indicator, verify or restore power to my ONT and check all connections. However, even the most robust systems can. Fiber optic networks are celebrated for their speed and reliability, but even the best systems can encounter problems. These high-speed, high-capacity communication networks are increasingly replacing copper cables, offering superior performance and. When your fiber optic network stops working, begin with a structured approach. Many fiber internet problems come from dirty connectors or loose plugs, not major faults. Back to top Once you're online, it's likely that you'll connect most of your devices to WiFi.