Why is the audio not working?

Check that the audio is not muted. To do this, simply increase the volume by pressing the volume up button on the side. If this does not help, then make sure that you can press the volume buttons and they are responsive. If the buttons are not responsive, then you might have to open the case and clean the surface underneath the button. For that, you can also refer to the guide How to clean and replace buttons. If you are unable to hear even after following these steps then you might have to replace your speakers. To replace, the speakers, you should follow this guide. Speaker replacement