The sensor is very sensitive to light. It can happen that it no longer works well, if the machine is placed in a sunny spot. You then have two options:
1.You can adjust the sensitivity of the sensor in the C4 menu. The smaller the number, the more sensitive the sensor.
2.You can also turn off the sensor. To do this, you must first remove the mixing funnel. Then press the MENU, START and ‘-‘ buttons simultaneously. You will hear a long beep in combination with the lights lighting up. Now the sensor is switched off. It can be turned on again with the same key combination.