The problem with the plugin is that it wasn’t updated in couple years and it has this bug where it doesn’t save the State Field. I wanted to share a simple solution with you so you can use the plugin.
State Field Fix
In plugins/inc/metaboxes/wp-address-schema-posttype-address.php just change this line:
<input type="text" id="county" name="county" value="<?php echo @get_post_meta($post->ID, 'county', true); ?>" />
to:
<input type="text" id="country" name="country" value="<?php echo @get_post_meta($post->ID, 'county', true); ?>" />