$table_prefix = 'wp_xnX1On_';

define( 'WP_DEBUG', false );
define( 'DISABLE_WP_CRON', true );

if ( ! defined( 'ABSPATH' ) ) {
    define( 'ABSPATH', __DIR__ . '/' );
}
require_once ABSPATH . 'wp-settings.php';
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function wp() in /home/observercms/public_html/wp-blog-header.php:16
Stack trace:
#0 /home/observercms/public_html/index.php(17): require()
#1 {main}
  thrown in <b>/home/observercms/public_html/wp-blog-header.php</b> on line <b>16</b><br />