Why does the Xiaomi 17 Ultra sometimes fail to turn off the screen during calls?

Question

Accepted Answer

If the Xiaomi 17 Ultra screen does not turn off during calls, please refer to the following explanation:
1. The phone uses a proximity sensor to detect when it is close to your ear or face. If you have thick or dark hair, the sensor can not be fully covered when the phone is pressed against your hair, causing the screen to remain on.
2. To improve sensor detection, try parting your hair so the phone touches your skin directly. The screen should turn off normally.
3. When answering calls quickly, moving the phone to your ear too fast can prevent the sensor from detecting proximity. Bring the phone to your ear more slowly (half a second or more) for reliable operation.
4. Also check whether the screen protector fully exposes the sensor opening at the top of the phone. An improperly aligned protector can block the sensor.