I have a very similar problem. My Wemo plugs worked perfectly fine until I added an xFi pod into the mix. When the plugs are connected to the pod they are non responsive. If I unplug the xFi pod I regain connectivity and they respond in my Home (iOS) app. I have also tried a PING test when the plugs are connected to the xFi pod and the PING is unsuccessful. In my xFi app everything is connected to the same network but it does not seem like the devices that are connected to the xFi pods are actually connected to the same network or at least devices connected to the gateway can't communicate to devices connected to the xFi pod.