If the field is within a repeater or flexible content field, you’ll need to use get_sub_field() instead of get_field().
If the field is within an options page or if you’re loop has a different post ID, you’ll want to use the second parameter of get_field as either:
get_field('enable_box','option');
or
get_field('enable_box', $post_id );
If it’s not either of those, add an image of your acf field setup and we should be able to see what’s happening.
