If your router is on, as indicated by the blue light, but you can't access the internet, the best way to resolve the issue is to perform a hard reset. This process clears all caches, refreshes the RAM, and restarts the router. In most instances, it resolves the problem and gets. If your fibre internet is not working, the quickest fix depends on the lights on your fibre box (ONT), router, or the behaviour you are experiencing. Called out engineer he said he managed to fixed the signal strength a day a go but this morning I lose the internet once more. Typically, these lights correspond to various router functions such as power. The LEDs on your modem, optical network terminal (ONT), router, or modem/router combo (gateway) are most likely blinking because they're communicating what the device is doing, or there's an error. Many fiber internet problems come from dirty connectors or loose plugs, not major faults.
[PDF Version]