What's wrong with the slave device link indicator light?
Make sure the WAN port connection is not loose. Some broadband lines because of long cable or poor network quality,
Check whether the WAN port is connected and check whether the cat connected to the WAN port is powered.
if WAN port lights are not bright, the interface may be damaged, please check if the power adapter specifications, specifications, and contact the office of inspection.
The front-end cable connected WAN port if the indicator light does not shine, connect the LAN normal, LAN port and WAN port directly connected by a cable
