1. Check whether the phone is in mute or vibration mode.
2. Adjust the ringtone size: slide down the screen top curtain-long press the sound icon to enter the sound interface-volume-ringtone, turn up the ringtone volume and try again.
3. If there is still no ringtone, please try to change the ringtone of the phone's built-in system.
4. Some machines support turning off all sound functions. It is recommended to enter Settings-Accessibility-(Hearing)-Turn off all sounds-Turn off.
5. If not, please back up the data (contacts, text messages, pictures, etc. ) in your phone, and then restore the factory settings.
If the problem still exists, please take the purchase invoice, maintenance card and machine to the Samsung service center, and the professional after-sales engineer will help you test it.