Clicking "The Conversation" sometimes doesn't work

Recently in Rocket French when I start an audio lesson I click on the button for "The Conversation" but it doesn't play.  (My usual routine is to play the conversation first to see how much I can understand on the first hearing.) 
It's sporadic, and if I try a previous lesson it works fine. Rocket Review works fine, the Interactive Audio Lesson works fine, in fact as far as I am aware all the other things work fine.
I'm currently working on 15.3.

Update - I've just checked this button in 15.4 and it works fine! But it's still not working in 15.3.

Hi Peter--252, 

Thank you for the message and feedback; I was also not able to play the Conversion in lesson 15.3; I have gone ahead and reported the issue to our team so they can review this and fix it as soon as possible. 

Kind Regards!
 

Hi Marie,

Thanks, I did wonder whether it was my operating system that was the problem but good (for me anyway) to know it isn't.

Pete