Irreverent message

What’s in the index.php file in WordPress root directory?

Do you mean its contents?

Yes. Especially check to see if there’s anything before the opening <?.

• This reply was modified 4 years, 6 months ago by Steven Stern (sterndata).

Thank you, I will check, but this issue from divi Builder or WordPress itself?, and What causes it?

I have noticed when I deactivate only the SG Optimizer plugin, the message disappears, and when I activate it, the message appears again.

this is the script of that plugin:

<?php
/**
* SG CachePress
*
* @package SG_CachePress
* @author SiteGround
* @link https://www.siteground.com/
*
* @wordpress-plugin
* Plugin Name: SG Optimizer
* Plugin URI: https://siteground.com
* Description: This plugin will link your WordPress application with all the performance optimizations provided by SiteGround
* Version: 5.6.7
* Author: SiteGround
* Author URI: https://www.siteground.com
* Text Domain: sg-cachepress
* Domain Path: /languages
*/

// Our namespace.
namespace SiteGround_Optimizer;

use SiteGround_Optimizer\Helper\Helper;
use SiteGround_Optimizer\Activator\Activator;
use SiteGround_Optimizer\Deactivator\Deactivator;

// If this file is called directly, abort.
if ( ! defined( ‘WPINC’ ) ) {
die;
}

// Define version constant.
if ( ! defined( __NAMESPACE__ . ‘\VERSION’ ) ) {
define( __NAMESPACE__ . ‘\VERSION’, ‘5.6.7’ );
}

// Define slug constant.
if ( ! defined( __NAMESPACE__ . ‘\PLUGIN_SLUG’ ) ) {
define( __NAMESPACE__ . ‘\PLUGIN_SLUG’, ‘sg-cachepress’ );
}

// Define root directory.
if ( ! defined( __NAMESPACE__ . ‘\DIR’ ) ) {
define( __NAMESPACE__ . ‘\DIR’, __DIR__ );
}

// Define root URL.
if ( ! defined( __NAMESPACE__ . ‘\URL’ ) ) {
$root_url = \trailingslashit( DIR );

// Sanitize directory separator on Windows.
$root_url = str_replace( ‘\\’, ‘/’, $root_url );

$wp_plugin_dir = str_replace( ‘\\’, ‘/’, WP_PLUGIN_DIR );
$root_url = str_replace( $wp_plugin_dir, \plugins_url(), $root_url );

define( __NAMESPACE__ . ‘\URL’, \untrailingslashit( $root_url ) );

unset( $root_url );
}

require_once( \SiteGround_Optimizer\DIR . ‘/vendor/autoload.php’ );

register_activation_hook( __FILE__, array( new Activator(), ‘activate’ ) );
register_deactivation_hook( __FILE__, array( new Deactivator(), ‘deactivate’ ) );

// Initialize helper.
global $siteground_optimizer_helper;

if ( ! isset( $siteground_optimizer_helper ) ) {
$siteground_optimizer_helper = new Helper();
}

I recommend asking at https://www.ads-software.com/support/plugin/sg-cachepress/#new-post so the plugin’s developers and support community can help you with this.