@MMaschine 

Hi,

It is highly likely that the WAN port's hardware is dead, especially since the cable works on other devices. However, before throwing it away, you should try these last three things:
1. Inspect the Port: Check inside the WAN port for bent copper pins, dirt, or debris.
2. Factory Reset: Hold the reset button for 10 seconds to clear any potential firmware glitches causing port detection failures.
3. The Workaround (Access Point Mode): If the WAN port is permanently broken, he can still use the device. Plug the internet cable into one of the working LAN ports, log into the router settings, and disable the DHCP server. It will no longer act as a main router, but it will work perfectly as a Wi-Fi Access Point.