If your fiber optic internet is available but the router cannot connect, the issue may be due to physical connections, router configuration, or the optical network terminal (ONT) status.

Check Physical Connections

Ensure all fiber and Ethernet cables are securely connected. Inspect the fiber cable for visible damage, sharp bends, or loose connectors, and clean connectors with lint-free wipes and isopropyl alcohol if necessary. Confirm the Ethernet cable from the ONT to the router's WAN port is properly seated and undamaged, and that the router and ONT are powered on and showing normal LED indicators (Power, PON, and Data) for fiber networks .

Restart Devices in Correct Order

Power cycle your network devices: unplug the ONT or modem first, wait 30–60 seconds, then plug it back in. After the ONT stabilizes, restart the router. This can resolve temporary glitches and allow the router to obtain a valid IP address .

Verify Router Configuration

Log in to your router's management page and check the WAN/Internet IP address. If it shows 0.0.0.0, the router is not receiving an IP from the ONT, indicating a connection or configuration issue. You may need to clone your computer's MAC address, manually set the router's LAN IP, or configure DNS servers as recommended by your ISP . Ensure the router firmware is up to date.

Test for Service or Outages

Confirm that your ISP is not experiencing a local outage. You can check via your ISP's website, mobile app, or by asking neighbors. If the ONT shows a red Alarm LED or the PON light is off, the problem may be with the fiber service itself, requiring ISP intervention .

Additional Steps

• Swap suspect transceivers or cables with known-good units to rule out hardware failure .
• Connect a device directly to the ONT via Ethernet to verify internet access; if it works, the issue is likely with the router.
• Avoid using surge protectors or extension cords for critical network devices to prevent power delivery issues . Following these steps systematically should help identify whether the problem lies with the fiber connection, the router, or configuration settings, allowing you to restore internet connectivity efficiently.