Error establishing database connection

Hello,

I’m trying to help a colleague with a failed Multisite implementation.

During development, WP was installed successfully with Multisite (sub-directory, not sub-domain) in a non-production environment. The site was pointed to a static IP address in wp-config.php.

When WP/Multisite was launched into production (online), the IP was changed to a URL. After it was changed to a URL, the site fails with this error message:

Error establishing database connection

Here is a scrubbed copy of the wp-config.php file:

<?php
/**
 * The base configurations of the WordPress.
 *
 * This file has the following configurations: MySQL settings, Table Prefix,
 * Secret Keys, WordPress Language, and ABSPATH. You can find more information
 * by visiting {@link http://codex.wordpress.org/Editing_wp-config.php Editing
 * wp-config.php} Codex page. You can get the MySQL settings from your web host.
 *
 * This file is used by the wp-config.php creation script during the
 * installation. You don't have to use the web site, you can just copy this file
 * to "wp-config.php" and fill in the values.
 *
 * @package WordPress
 *
 */

// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'SOMENAME_wrdp5');

/** MySQL database username */
define('DB_USER', 'SOMENAME_wrdp1');

/** MySQL database password */
define('DB_PASSWORD', 'SOMEPASSWORD');

/** MySQL hostname */
define('DB_HOST', 'SOMEURL');

/** Database Charset to use in creating database tables. */
define('DB_CHARSET', 'utf8');

/** The Database Collate type. Don't change this if in doubt. */
define('DB_COLLATE', '');

/**#@+
 * Authentication Unique Keys and Salts.
 *
 * Change these to different unique phrases!
 * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}
 * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.
 *
 * @since 2.6.0
 */
define('AUTH_KEY',         'SALT');

define('SECURE_AUTH_KEY',  'KEY');

define('LOGGED_IN_KEY',    'KEY');

define('NONCE_KEY',        'KEY');

define('AUTH_SALT',        'SALT');

define('SECURE_AUTH_SALT', 'SALT');

define('LOGGED_IN_SALT',   'SALT');

define('NONCE_SALT',       'SALT');

/**#@-*/

/**
 * WordPress Database Table prefix.
 *
 * You can have multiple installations in one database if you give each a unique
 * prefix. Only numbers, letters, and underscores please!
 */
$table_prefix  = 'wp_';

/**
 * WordPress Localized Language, defaults to English.
 *
 * Change this to localize WordPress.  A corresponding MO file for the chosen
 * language must be installed to wp-content/languages. For example, install
 * de.mo to wp-content/languages and set WPLANG to 'de' to enable German
 * language support.
 */
define ('WPLANG', '');

/**
 * WordPress Multisite settings.
 * Note that the available documentation on Multisite configuration is ... somewhat lacking (I'm being generous).
 */
define( 'WP_ALLOW_MULTISITE', true );
define('MULTISITE', true);
define( 'SUBDOMAIN_INSTALL', false );
$base = '/';
define( 'DOMAIN_CURRENT_SITE', 'SOMEURL.com' );
define( 'PATH_CURRENT_SITE', '/' );
define( 'SITE_ID_CURRENT_SITE', 1 );
define( 'BLOG_ID_CURRENT_SITE', 1 );

/**
 * For developers: WordPress debugging mode.
 *
 * Change this to true to enable the display of notices during development.
 * It is strongly recommended that plugin and theme developers use WP_DEBUG
 * in their development environments.
 */
define('WP_DEBUG', false);

/* That's all, stop editing! Happy blogging. */

/** Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
    define('ABSPATH', dirname(__FILE__) . '/');

/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

//

I’m a professional PHP developer, and have been a Moderator on Devshed.com for almost a decade. However, this is my first foray into WordPress; before I start wholesale re-coding how WP handles database connectivity for Multisite installations, I wanted to see if anyone had recommendations on how to resolve this issue.

Thanks.