AjaxQ jQuery plugin always undefined

I’m trying to use the AjaxQ plugin with jQuery to queue some ajax requests but seems to be just undefined whatever I try.

Getting the following error:

TypeError: Cannot read properties of undefined (reading 'isRunning')

jsfiddle Demo

The code is super simple, the AjaxQ library is included, and I’m just doing this console log as an initial step to see if the library is working properly, before even writing any other code:

$( document ).ready(function() {
    console.log($.ajaxq.isRunning('Test'));
});

What am I missing here?