Unable to hear the called people
Usually following net calls using Facebook messenger or Duo Appl . I can’t do normal call as I can’t hear the one who I called and I should restart the phone to function normally !
What can I do to repair this
If you are able to hear sound properly except on cellular calls in particular cases as you describe, then the problem is likely to be software rather than hardware.
See if there is an update for either app, and if not, uninstall them and reinstall them to see if that solves the problem. If that does not work report the issue to the developer together with your phone model, iOS version and carrier.