audio not working

hi,
I use WOW slider ver 7.3 on my website which I like very much indeed,
but sadly it is not playing my audio file.

it is a quite small (normal mp3, correctly added to the slideshow in settings/general.
I have it located in the same folder as the html file, and all has been uploaded to my servers correctly.

I have tested it in Firefox and Chrome, but no sound!
if memory serves, I believe I have had it working a long time ago with earlier wowslider versions.
any help would be really appreciated.
thanks,
Kevin

https://wordpress.org/plugins/wowslider/