Welcome to Android Central! More details would help. What version of Android? Rooted or unrooted? Under what circumstances does this seem to happen? Is it only media sounds that cut out, or also ringtones and notifications? Do you get any error messages? Do you have to reboot to bring the sound back? What happens if you go to Settings>Sounds>Ringtones, and select any ringtone to sample--does it "wake up" the sound? (The last thing used to happen to my old Razr Maxx.)