When I turn the drone, the back lights have a strange combo, not listed in the manual: The leg to the left of the battery has a slow green light, but the leg to the right of the battery has a slow yellow light. Both are flashing at the same time, but not the same color. I don't know what to make of that. The WiFi is working and I see the camera image on the app, but I can't power up the rotors. Any ideas folks?