Why is my PowerPoint presentation not displaying inserted audio on a specific slide?

Check the Audio Settings

Check your audio settings to see if an audio track is selected and playing in your slide.
Check for Missing Media

If the audio track is playing, then check the Media Library for any missing or incorrect audio files.
Check Sound Volume Levels

Make sure your presentation's sound volume is not too loud or too soft.
Check Audio File Format

Make sure the audio is supported by PowerPoint and is in one of the related file formats (.wav, .wma, etc).
Verify Software Version

Make sure you are using the latest version of PowerPoint.