The most common causes of this are loss of power to the fiber terminal (ONT) or an unplugged network cable. Here's an example of LEDs to look for if you have fiber internet and an ONT: The Power LED. We have a fibre run, SM, 650 meters, with Level1 dumb switches at each end, I get Link lights at both ends, but there's no network traffic. Switch A is on the router end, devices connected to this switch get DHCP leases and can browse the internet without issue. In many cases, a fiber connection problem originates from one of the following four devices: Router: Creates your Wi-Fi network in your home or business. Check LED lights. Fiber optic networks are celebrated for their speed and reliability, but even the best systems can encounter problems.
