The following actions are recommended: 1. This may be because the option to turn off all sounds is set. It is recommended to turn off all sounds through phone settings-(My device/device)-Auxiliary functions-(Monitoring) and uncheck it. 2. Set-Sound-Volume and try to turn up each volume. 3. If it is invalid, please back up data (contacts, multimedia files, etc.). ) and restore the phone to the factory settings. If the problem still exists, please take the purchase invoice, maintenance card and machine to Samsung service center for inspection by engineers.