Iphone 12 Pro cannot hear outbound ringing or if connects, but speaker phone works fine

When I call someone and hold phone to my ear, I can't hear ringing or if they answer...phone is totally silent. But, if I put the SAME call on speakerphone, I hear fine and phone seems fine. This has just started happening. Rebooting phone isn't fixing and no Mute setting is on. Thoughts? Weird problem.