Your phone app - Bluetooth is connected but can't hear calls

Hey,

I am trying to make calls trough my PC.

I have problem with connecting the audio when having a call to my PC nevertheless with my Android phone there is Bluetooth connection. 

1. I am able to make and receive calls but the audio does not come through my headphones. Even if I try to toggle (Off) the "Use phone" option in the call window it reverts back turning it on within a second. (not a bit of audio for the second too).

When I do it I receive error message "Can't make the call. Make sure your device is connected to Bluetooth, then try the call again.",  as depicted in the image below.

2. I tried switching the audio on my phone to the laptop (Bluetooth) it also reverts back within a second.
3. When receiving an incoming call I get a similar error message "Can't receive call audio on this this device. Accept on phone instead" , I added a screenshot of the error below

I already tried to unpair the Bluetooth connection and setup again the connection trough your phone app, but still didn't work

Restarted both PC and my Android phone, didn't help.

Is there a solution for this?

Note: This is not a sound issue.