1. Possible cause: The cable is connected incorrectly or the interface of the network cable is improperly connected. Workaround: Make sure the main line is plugged into the router's WAN port.
2. Possible causes: The indoor network cable is aging, poor quality, or too long, resulting in excessive line attenuation. Workaround: Try adjusting the rate mode of the router's WAN port. Log in to the router management interface, click Advanced Settings > > Network parameters > > WAN port Settings, WAN port rate Settings select 10Mbps half-duplex or 10Mbps full duplex mode, and click Connect. Note: Some routers or some software versions do not support adjusting the WAN port rate mode. Try to upgrade the router software version.
3. Possible cause: The Modem is not powered on or the cable is faulty. Solution: Remove the router, single machine connection broadband, to ensure that the computer directly connected broadband can be normal Internet access, to eliminate broadband lines or cat problems.
4. Possible cause: The WAN port on the router is broken. Solution: Connect the two ends of a network cable to the WAN port and one of the LAN ports. If the WAN port indicator is still not on, the WAN port of the router may be faulty. Check whether the power specifications of the power adapter match those on the label on the bottom of the router. If yes, contact the office for maintenance.