Can't get plugin to work, throws JS error

This looks like an awesome plugin and exactly what I need, but I’m having a bit of trouble getting it to work.

I have it installed in a brand new WP 4.5.3 site with no other plugins activated, but I get no syntax highlighting in any edit screen anywhere in the site (Posts, pages, theme editor, etc.).

The error showing in the console is:

Uncaught ReferenceError: mivhak_settings is not defined mivhak.min.js?ver=1.3.6:1

Any idea what could be causing this and how to remedy it? Thanks!

https://wordpress.org/plugins/mivhak/