Sensor not properly working

[Sooru]

I bought Sony Xperia C4 dual and it's screen not working properly. when ever i make calls it's screen goes off.when i approached sony service centre they are sayin no problem with the phone.

[_alexdon_]

The screen will go off during calls if the sensor is covered. In this case, do you have something covering it?

[Uliwooly]

@Sooru

Settings > about phone > diagnostics > test > test the proximity sensor