sound problem in natural20

HI all. I have recently purchased natural 20. I'm quite impressed with the app. 4 rand is really next to nothing. By the way rand is the currency in south Africa. I
need some help please. I would like to know if natural 20 has a sound of a dice when I tap the roll button. I went into settings. I go into the settings app on the
home screen and from there go into the app settings for natural 20. And there is a setting that says play sounds. the setting is on but there is no sound when I tap
on roll. how can I fix this problem? Many thanks for any help. NIcol