WordPress Audio Player Plugin – Not on Page & Not Appearing

Used to have the WordPress Audio Player Plugin working fine on this page: https://www.iradiosales.com/promotionaltools (now, as you can see, not so much).

I don’t even get the add audio panel to come up when I click the add audio link in WP (as described here: https://wpaudioplayer.com/usage).

Any thoughts on the problem? I can’t find any fixes via the WP Audio Player site.