I just got 3 more B & W lights. One problem I seem to keep having is that sometimes not all lights will respond. For example, I have 3 lights in my living room. When I give the command to either turn them off or on, once in a while one light will not work. When I go into the Hue app on my iPhone, it says that it's "unreachable" but when I tap on it in the app, it responds so it clearly is reachable. I'm not sure if it's just my hub placement or what. Any suggestions?