Diagnose & Fix Possible Issue with wp-blog-header.php

In a test dir with its own table, when I change the path to the wp-blog-header, I get the error ‘Sorry, no posts…”

How can I diagnose a possible issue with that file?
test dir ‘wp-blog-header.php’

<?php
/**
 * Loads the WordPress environment and template.
 *
 * @package WordPress
 */

if ( !isset($wp_did_header) ) {

	$wp_did_header = true;

	require_once( dirname(__FILE__) . '/wp-load.php' );

	wp();

	require_once( ABSPATH . WPINC . '/template-loader.php' );

}

?>