Why my microphone is not working during calls?

[AC Question]

I have a strangest issue with the microphone on my Samsung galaxy S7.

When I make a call, the person I am calling cannot hear me. Simply it is like the microphone was not working at all.

But:
1. Both microphones work, which I can confirm by recording a video and blowing into microphone holes on both sides of the device. I can hear hisses for each blow. Microphone does work while calling through Hangouts, Skype, etc.
2. During the call when I switch on the speakerphone the microphone still does not work [I know that, when having issues with the bottom mic that would help].
3. When I connect audio headphones (they DON'T have a microphone) the microphone on the phone starts to work. When I disconnect it stops working.

The last point renders the issue quite weird for me. It seems that it is not a hardware one. I have tried factory reset, wiping cache. Nothing helps.

Anybody had a similar issue or any clue what to do?

Cheers,
albeercik

 

[the tall guy]

Hi, I'd suggest taking the phone back and getting a new one as this doesn't sound like normal practice for the phone.