My new iphone 8 stopped making all sounds a few days ago. I finally sat down to investigate. Took awhile to figure out an easy answer. On the side of the phone where the volume buttons are there is a very small grey tab at the top. To the left ringer OFF. To the RIGHT ringer on,. I was fooling around with these and must have inadvertently click to off. My old iphone 6 has the same setup. Hope this helps someone.