Custom Fields issues

Hello,
I’m currently having some issues with “New User Registration – For Admin” template.

I created some extra user profile fields into the WP Registration Form with the “Advanced Custom Fields” plugin (How to Add Additional User Profile Fields in WordPress Registration – Method 1) but I cannot add them into the notification’s message body.

[user_custom_field field=“X”] and [custom_field field=“X”] shortcodes don’t seem to be working.

What’s the problem?
Do I have to buy the “Custom Fields” Add-on or am I using the wrong shortcodes?

Thank you in advance.