Nokia Lumia 820 - I cannot hear the other person in a call

  1. While in a call, increase the volume by pressing the volume keys on the side of the phone.
  2. Make sure nothing is plugged into the audio connector.
  3. If the problem persists, switch your phone off and on. After this operation, you may need to re-adjust the volume.
  4. Set your phone to loudspeaker mode or try a wired headset.