I can't hear the other person on the phone with my new iphone 6s plus

When I make calls on my new iPhone 6s plus, I cant hear the person on the other end, regardless of who initiated the call. I can only hear them if I use the speaker. If I initiate the call, I can't hear the phone ringing (except on the speaker). I turned off Wifi Calling, Calls on Other Devices and TTY. And I also re-set my phone by holding down the home button and off button for 10 seconds.