I have a Samsung Galaxy SII HD LTE with a Cyanogenmod custom ROM. After WhatsApp inroduced the calling feature I updated the app and asked a friend to call me. I answered the call and disconnected it. Afterwards my microphone doesn't seem to be working when I'm taking calls, not in speakerphone mode either and not even if I plug in a hands-free. But the voice recorder seems fine. The issue is there only when I make calls, regular and WhatsApp both. Then I factory resetted the phone and microphone started working! The problem happened again when I made a call through WhatsApp after resetting. How can I resolve this issue and make WhatsApp calling work??