I am not really sure what happened. Drone just displays that message now.
Seems to be a delicate thing inside the drone (the sensor you describe).I gave it a thorough session of battery attempts. At one point the alarm delayed for about ... 5 seconds. Then re appeared. I think once that switch is tripped, the quads disabled, tbh. Its a relay, with a connection, and the switch, and I think inside it, its "broken". The switch is the most tiny thing I ever seen too, take a look inside the batter compartment with an eye piece. They are under the metal sensor.