Why is my iPhone not ringing?

There are a number of reasons your phone might not be ringing. You might have the mute switch engaged. It's the little slider over the volume buttons. You might have the volume turned down. Check in Settings>Sounds & Haptics. Or, you might have Do Not Disturb enabled. Check Settings>Do Not Disturb.

Have you made sure that you have an audible ringtone selected?

This is a kind of weird one but worth trying.

Go to Settings>Accessibility>Touch and turn on Assistive Touch. Then, go to Customize Top Level Menu. If Mute is not already one of the icons, add it. Exit that screen. Press and hold the Assistive touch button that appears on your screen. Tap Mute, then unmute.

You can turn off Assistive Touch when you're done.

In order to get rid of Assistive Touch, you need to go back to Settings>Accessibility>Touch and turn it off.

It hitting mute/unmute may or may not resolve your problem. It's just something to try.

Then you don't need to worry about those settings. What about the mute switch and volume, did you check those?

pwwwayne wrote:

There is a checkmark at "Silence while iPhone is locked," but the only other choice is "Always".

How to remove the checkmark?

How do I Lock/Unlock iPhone?

Those don't mean anything unless Do Not Disturb is enabled. Is it?