Huawei router cannot access the internet when plugged into fiber optic cable

If your Huawei router cannot access the internet via a fiber optic connection, the issue is often due to incorrect WAN port setup, PPPoE credentials, or compatibility with the optical network terminal (ONT).Check Physical ConnectionsEnsure the fiber optic cable is properly connected to the Huawei ONT and that the ONT is powered on with a green status light. The router should be connected to the ONT LAN port 1 (PORT1) using an Ethernet cable, and the cable should be securely plugged into the router's WAN port if it is not a self-adaptive WAN/LAN port . Avoid unplugging the optical cable, as this can disrupt the PON connection.Verify Router SettingsLog in to the router's web-based management page (usually at 192.168.3.1) and check the Internet access mode. If your ISP uses PPPoE, ensure the broadband account name and password are correctly entered, as these are case-sensitive . Save the settings and restart the router. If the router supports automatic WAN/LAN detection, it may select the correct mode automatically, but manual configuration may be necessary in some cases.Check IP Address AssignmentEnsure that devices connected to the router can obtain an IP address from the DHCP server. By default, the router assigns addresses in the 192.168.3.2–192.168.3.254 range. If a device does not receive a valid IP, it will not access the internet .Test Direct ConnectionTo isolate the problem, connect a computer directly to the ONT using the same Ethernet cable and attempt a PPPoE login with your ISP credentials. If the computer can access the internet, the issue is likely with the router configuration. If it cannot, the problem may be with the ONT or ISP service .Consider Compatibility IssuesOlder Huawei routers, such as the EchoLife HG8546M, may be incompatible with newer gateway modems provided by some ISPs. In such cases, the router may connect to the WiFi network but fail to access the internet, as it does not communicate properly with the ISP's network . Contact your ISP to confirm compatibility or consider using the ISP-provided modem/router as the primary device.Additional TipsReplace the Ethernet cable if the connection is unstable.Restart both the ONT and the router after configuration changes.Check for parental controls or firewall settings that may block internet access.If the PON light on the ONT is off or flashing, contact your ISP for service verification . Following these steps should help identify whether the issue is due to physical connections, router configuration, or ISP compatibility, allowing you to restore internet access on your Huawei router.