Sound problem while making a call. All components work

I've have tested the microphone, earspeaker and speaker in other apps. They work fine. But when i'm making a call.. No sound at all. I can't hear the caller and the caller doesn't hear me. Even de speaker won't work.

When the call starts, the speaker is immediately on and the proximity sensor doesn't work either. When I tap the speaker on off on the proximity sensor works again and dims the screen.

I received this phone with this problem after it fell on the ground. The glass was broken, so i replaced the screen. But the sound problem still exist.

I don't understand why this only occurs only when calling someone. After all the components do work properly..