No internet connection with fiber optic router

No internet from a fiber optic router can result from cable issues, ONT or router faults, configuration errors, or ISP outages.Step 1: Check Physical ConnectionsEnsure all cables are securely connected. The fiber optic cable should be properly plugged into the Optical Network Terminal (ONT), and the Ethernet cable should connect the ONT to the router's WAN port. Inspect cables for visible damage, bends, or fraying, and clean connectors with lint-free wipes and isopropyl alcohol if necessary .Step 2: Power Cycle DevicesRestart both the ONT and the router. Unplug them from power, wait 30–60 seconds, then plug in the ONT first, wait for its lights to stabilize, and then power on the router . This can resolve temporary glitches or firmware-related issues.Step 3: Verify Router and ONT StatusCheck the indicator lights on both devices. A “LOS” (Loss of Signal) light on the ONT indicates a fiber signal problem, while WAN or internet lights on the router indicate connectivity status . If lights show errors, the issue may be with the fiber line or ONT hardware.Step 4: Inspect ConfigurationLog into the router's admin panel (usually via 192.168.0.1 or 192.168.1.1) and verify settings such as IP assignment, DHCP, and firmware updates . Incorrect configurations or outdated firmware can prevent internet access.Step 5: Test for ISP OutagesConfirm whether your ISP is experiencing service interruptions. Use a mobile device on cellular data or check the ISP's status page. If there is an outage, internet access will be restored once the service is back online .Step 6: Advanced DiagnosticsIf the above steps fail, test the fiber signal with an optical power meter or swap the ONT or router with known working units to isolate hardware faults . Persistent issues may require contacting your ISP for line testing or replacement of faulty equipment. By systematically following these steps—checking cables, power cycling, verifying device status, reviewing configuration, and confirming ISP service—you can identify and resolve most causes of no internet access from a fiber optic router.