R6400 - Ethernet not working, Wifi does

I bought my router new in March and it has been working until today.  The wifi works well.  However, I am unable to connect via the ethernet to take advantage of faster speeds.  I tried all 4 ports and 3 cables.  The lights are white/light blue on the router appearing as if they are working, but when I connect to my laptop it either only briefly connects or does not connect at all to the internet.  As the wifi works I have to assume the internet service and modem are working, and that the issue is at the router level.

Please help!