Download Button (Sorry something went wrong)

You can see the problem happen here:
http://www.djxcon.com/?page_id=120

I have my mp3 files located here:
http://djxcon.com/files

The player plays the music just fine.

I can right-click the download button to download the file and that works.

Here is the Problem
When I click the download button, I get “Sorry, something went wrong!”

To troubleshoot, I tried using that download.php file and sourcing the directory in the downloads settings, but that did not help.

What am I doing wrong?

https://wordpress.org/plugins/mp3-jplayer/