Another common problem is starting the Drone and then starting the RC, but not having the two within 12" of each other. Any further apart, and especially if you open the App on your iPhone, the RC and Spark don't have a chance to establish their 'dedicated' WiFi connection. You end up (as Guerrac points out above) with the iPhone WiFi connecting directly to the Spark. That's why using the OTG cable is so handy. It allows you to turn the iPhone WiFi OFF so it doesn't get in the way.