I am running the plugin WP Show Posts on a WP install with a custom post type (called 'trees') that has a custom post field called 'popularity' (formatted as “number”). The custom field was created by the Advanced Custom Fields plugin, the custom post type with the plugin Custom Post Type UI.

Now, I want to create a list, that only shows posts with a popularity value below the numeric value of 10.

To do so, I have followed the plugin author's instructions here and adjusted the plugin itself to allow for additional arguments.

I now use the following code, as suggested in this support article, but unfortunately, I can not get it to work. The output is the “no results message”.