Tesla model 3: ecall emergency call system needs service on tesla

Description:
An error shows up on the screen: _ecall emergency call system needs service_

Solution:

Within ten seconds:
a. Press the SOS call button in the roof of the car and cancel the call immediately on the screen.

b. Hard reboot the car by pressing the brake pedal and the two buttons on the steering-wheel.

The error should be cleared after that.