I'm on my third Cisco DPC3941T having the same problem. My house was pre-wired with CAT 5e cable, so I use wired connections where I can. I have two of the four ports going directly to my smart TV and one PC. I use the third going to a D-Link 4-port switch. I also have the WiFi activated for tablets and smartphones. From time to time, one or more of the Ethernet ports on the gateway stops working. After one or more power cycles, they come back. I'm thinking about buying a different gateway and avoiding the rental fee. I'm also thinking FIOS.