Maybe a temporary software-related issue prevents your device from ringing. Try restarting your device and your device should start ringing.
See the don't know how to restart my device guide if you are not sure how to restart your device.
It is possible that the ringtone you set to notify you when someone is calling you or when you receive notifications of any kind is deleted or moved to a different location. Try setting another ringtone in the device's settings.
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.