iPhone does not ring.

My iPhone (7 plus, ios 12.3.1) does not ring or notify me when there's a text. It used to do so, but now it doesn't, and I can't figure out why. The ringer is on, and turned up. The do-not-disturb is off. All the settings are set to ring and to notify me. The bluetooth is off, so there's no connection misrouting the sound. The only thing I can find is that the "silence when screen is locked" feature under DND is on, but the DND is off, so that shouldn't matter. I just did a test, calling myself from a different phone, and the ringer doesn't sound, whether or not the screen is on. The screen does light up and show that I'm getting a call, but unless I'm looking at the phone when someone calls, I'm not going to see it.