Verify wp-config.php Database Credentials

This is the most critical first check. Connect to your server via FTP/SFTP and locate the wp-config.php file in your WordPress root directory. Open it in a text editor and carefully compare the values for DB_NAME, DB_USER, DB_PASSWORD, and DB_HOST against the actual database credentials provided by your host or found in your hosting control panel (e.g., cPanel's MySQL Databases section). Even a single character mismatch will cause an error.

define('DB_NAME', 'your_database_name');
define('DB_USER', 'your_database_username');
define('DB_PASSWORD', 'your_database_password');
define('DB_HOST', 'localhost'); // Often 'localhost', but can be an IP or hostname

✓ Time estimate: 5-10 minutes. Ensure exact case-sensitivity and no trailing spaces.

Confirm Database User Permissions

Even with correct credentials, the database user might not have sufficient permissions. Log into your hosting control panel (e.g., cPanel) and navigate to the MySQL Databases section. Find the user associated with your WordPress database and ensure it has ALL PRIVILEGES granted for that specific database. If using phpMyAdmin, you can check user privileges under the 'Users' tab. If you suspect a wordpress database access denied error, revoking and re-granting privileges can sometimes resolve underlying issues.

-- Example SQL to grant permissions (execute in phpMyAdmin SQL tab if comfortable)
GRANT ALL PRIVILEGES ON `your_database_name`.* TO 'your_database_username'@'localhost';
FLUSH PRIVILEGES;

✓ Time estimate: 5-15 minutes. Be careful with SQL commands; incorrect syntax can worsen issues.

Verify Database Existence and Name

Access phpMyAdmin (usually via your hosting control panel) or your host's database management interface. Cross-reference the DB_NAME from your wp-config.php with the list of databases available. If the database name doesn't exist, or if it's misspelled, you'll encounter a wordpress database not found error. If it's a new site or migration, ensure the database was actually created and imported correctly. If you're seeing a database connection error after migration, this is a prime candidate.

✓ Time estimate: 3-7 minutes. Crucial for confirming the target database exists.

Validate DB_HOST and Server Connectivity

The DB_HOST value is critical. While often localhost, some hosts use specific IP addresses or hostnames. Confirm this with your hosting provider. If DB_HOST is an external IP/hostname, try pinging it from your server's SSH terminal (if you have access) to check connectivity. If the database server is simply down or unreachable, even correct credentials will fail, leading to a general Error Establishing a Database Connection. For a woocommerce database connection error, an intermittently unreachable host can cause problems under load.

# Example command if DB_HOST is not 'localhost'
ping your_db_host.com

# Or, attempt a direct MySQL connection from SSH
mysql -u your_database_username -p -h your_db_host.com your_database_name

✓ Time estimate: 10-20 minutes. Requires SSH access or direct host confirmation.

Check Database Table Prefix

In wp-config.php, there's a variable $table_prefix (e.g., $table_prefix = 'wp_';). This prefix must exactly match the prefix of your WordPress tables in the database (e.g., wp_options, wp_posts). Log into phpMyAdmin, select your database, and examine the table names. If the prefix in wp-config.php doesn't match, you have a wordpress database prefix error, which will prevent WordPress from finding its tables, often resulting in a "Table 'database_name.wp_options' doesn't exist" error. This is a common issue after a WooCommerce migration.

✓ Time estimate: 5-10 minutes. A mismatch here is a definitive showstopper.

Multisite-Specific Configuration Review

If you're running WordPress Multisite, beyond the standard credentials, review your wp-config.php for multisite-specific constants like SUBDOMAIN_INSTALL, DOMAIN_CURRENT_SITE, PATH_CURRENT_SITE, and SITE_ID_CURRENT_SITE. Ensure these are correctly set. Also, verify that the database user has permissions to access all necessary tables across the network. A wordpress multisite database error can be complex, sometimes requiring a deeper look into the wp_blogs and wp_site tables in the database itself. If you're seeing issues during WooCommerce initial setup on a sub-site, this is particularly relevant.

✓ Time estimate: 15-30 minutes. Multisite configurations add layers of complexity.