Auth interceptor isn't firing

I’m using as my auth interceptor but for some reason it’s not firing.

Its job is to fire the “event:auth-loginRequired” event whenever the error code 401 is received.

In my app.js on run:

$rootScope.$on(‘event:auth-loginRequired’, function(event, data){
console.log(‘login required’,data);

Any idea why it won’t fire? No console errors, nothing. I’ve included the plugins JS file, added it to the modules etc. but having no luck.