Fixing WordPress Database Connection Errors After Migration

The "Error Establishing a Database Connection" Message

After migrating WordPress to a new host, the most common cause is incorrect credentials in wp-config.php.

Checklist

1. Verify DB_NAME, DB_USER, DB_PASSWORD, and DB_HOST match the new server.
2. Confirm the database user has ALL PRIVILEGES on the database.
3. Check the table prefix ($table_prefix) matches the migrated tables.
4. Repair tables if needed by adding to wp-config.php:

   define('WP_ALLOW_REPAIR', true);
   

   Then visit /wp-admin/maint/repair.php.

Reading the DB Error Log

WordPress database errors are written to debug.log as:

WordPress database error Table 'wp_db.options' doesn't exist for query SELECT... made by require('wp-blog-header.php')

Use the FormatHub WordPress Parser to beautify the failing query and the call path so you can identify which migration step missed a table.