iphone does not ring when someone is calling

Things to check:

• FIRST, the Mute switch on the left side of the phone above the volume buttons. It should be towards the screen and should not show any color when you look in it.
• Volume buttons - While the Home screen is displayed, press the upper button to make the sound louder
• Do not Disturb - Go to Settings/Do Not Disturb and verify that it is off, and that the Scheduled feature does not have it muted
•  Watch - If you have a watch connected the ring will signal on the watch rather than the phone.