LOS stands for Loss of Signal , the ONT can't detect a Fiber signal from the ISP. Common causes: loose Fiber cable, dirty SC/APC connector, ISP outage, or ONT stuck after a power cut. If you find that the Optical/Config/PON Light on your Fibre ONT (Optical Network Terminal) box is flashing, has gone off, or has gone red, this indicates there may be an issue with the fibre connection coming into your property. Most LOS errors clear with a cable check and ONT restart, no technician needed. A healthy Openreach. The Power light is usually the first light to check when troubleshooting your ONT. Red: The ONT is not receiving power or has a power-related issue. Its lights should all glow a steady green. Ive seen the kits to do those but at my company those are forbidden. Thanks! I'll give them a ring tomorrow hopefully.
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