Just spent like an hour or two trying to diagnose and fix my sister's iPhone, because it wasn't making or receiving calls (unless WiFi Calling was turned on and the phone was within range of a recognized WiFi network, such as the home network here, in which case it could make and receive calls). You want to know how I finally "fixed" it? It randomly occurred to me to just try turning the damn thing off and back on again. And when it did occur to me, I said that it should have been the first thing we tried. And, indeed, that's what "fixed" the phone. It's something that my sister (and my other sister and my brother) didn't think to try at all, and it's something that I didn't think to try until an hour or two into futilely going through settings and shit.
We still have no idea what caused the phone to not be working properly for the past half a week or so now (and today was the first I'd heard of it), but we do know that rebooting it somehow magically made those problems go away.
So, note to self, for future reference: if you're having phone/computer/electronic problems, step #1, before trying any damn thing else, is literally "try turning it off and back on again."
We still have no idea what caused the phone to not be working properly for the past half a week or so now (and today was the first I'd heard of it), but we do know that rebooting it somehow magically made those problems go away.
So, note to self, for future reference: if you're having phone/computer/electronic problems, step #1, before trying any damn thing else, is literally "try turning it off and back on again."