How to Fix “Error Establishing a Database Connection”

The “Error Establishing a Database Connection” message is one of the most serious WordPress errors. When it appears, your website usually becomes completely inaccessible.

This error means WordPress cannot communicate with its database. Since WordPress stores posts, pages, users, settings, and plugins in the database, the site cannot load anything without it.

The good news is that this error is usually fixable. So, why it happens and which checks to run in the correct order?

What Does “Error Establishing a Database Connection” Actually Mean?

WordPress connects to a MySQL (or MariaDB) database every time a page loads.

The connection requires:

• database name
• database user
• database password
• database host

If any part of this connection fails, WordPress stops and shows the error.

This is not a browser issue. This is not a theme issue. This is a server-level or configuration problem.

Most Common Causes of the “Error Establishing a Database Connection” Error

Before fixing anything, it helps to know the real causes.

1. Incorrect Database Credentials

The most common reason is incorrect login details in wp-config.php.

Even one wrong character in the password is enough to break the connection and show Error Establishing a Database Connection

2. Corrupted Database Tables

Database corruption can happen because of:

• plugin or theme bugs
• failed updates
• server crashes
• disk issues

When WordPress cannot read required tables, the connection fails.

3. Database Server Is Down

Sometimes the database server itself is offline.

This often happens on:

• shared hosting
• overloaded servers
• during hosting maintenance

In this case, credentials are correct, but the server is unreachable.

4. Hosting Resource Limits

High traffic or poorly optimized plugins can overload the database.

When the database reaches connection limits, new connections are refused.

5. Recent Migration or Hosting Change

After moving a site to a new host, database details often change.

If wp-config.php is not updated, WordPress will still try to connect to the old database.

Step 1: Check Database Credentials in wp-config.php

Start here!

Open the wp-config.php file in your WordPress root directory.

You should see something like this:

define( 'DB_NAME', 'database_name' );
define( 'DB_USER', 'database_user' );
define( 'DB_PASSWORD', 'database_password' );
define( 'DB_HOST', 'localhost' );

What to Verify

• DB_NAME – the database actually exists
• DB_USER – the user exists and has access
• DB_PASSWORD – correct password
• DB_HOST – matches your hosting provider

Some hosts use custom hosts, for example:

define( 'DB_HOST', '127.0.0.1' );

or

define( 'DB_HOST', 'mysql.yourhost.com' );

If you are unsure, your hosting provider can confirm the correct values.

Step 2: Test Database Connection Manually

If credentials look correct, test the connection directly.

Create a temporary file called db-test.php in the WordPress root:

<?php
$connection = new mysqli(
    'localhost',
    'database_user',
    'database_password',
    'database_name'
);

if ( $connection->connect_error ) {
    die( 'Connection failed: ' . $connection->connect_error );
}

echo 'Database connection successful';

Open this file in the browser.

• If it fails → credentials or server problem
• If it works → WordPress configuration or database corruption

Delete this file after testing.

Step 3: Repair a Corrupted Database

WordPress includes a built-in database repair tool.

Enable Repair Mode

Add this line to wp-config.php:

define( 'WP_ALLOW_REPAIR', true );

Then visit:

https://yourwebsite.com/wp-admin/maint/repair.php

Click Repair Database or Repair and Optimize Database.

After the repair completes, remove the line from wp-config.php.

Step 4: Check Database Tables Directly

If repair does not help, inspect tables manually using phpMyAdmin.

Look for:

• missing tables
• tables marked as “corrupt”
• errors during queries

Common WordPress tables include:

• wp_posts
• wp_options
• wp_users
• wp_usermeta

If critical tables are missing, restoring a backup may be required.

Step 5: Check If the Database Server Is Down

If credentials and tables are fine, the database server may be unavailable.

Signs of server issues:

• other sites on the same host are down, and have Error Establishing a Database Connection issue
• database connection works intermittently
• errors appear only during peak traffic

Contact your hosting provider and ask:

• is the database server running?
• are there connection limits?
• was there recent maintenance?
• are there Error Establishing a Database Connection issues on other sites they host?

On shared hosting, this is a very common cause.

Step 6: Increase Database Connection Limits

On some servers, database connections are limited, and this may cause an Error Establishing a Database Connection issue

You can try adding this to wp-config.php:

define( 'WP_USE_EXT_MYSQL', true );

Or increase PHP memory:

define( 'WP_MEMORY_LIMIT', '256M' );

This does not fix bad hosting, but it can reduce errors temporarily.

Step 7: Disable Plugins to Reduce Load

If the site loads intermittently, a plugin may be overloading the database.

Rename the plugins folder via FTP:

/wp-content/plugins → /wp-content/plugins-disabled

If the site loads, reactivate plugins one by one to find the culprit.

Heavy plugins often include:

• poorly optimized page builders
• analytics plugins
• backup plugins running too often

Step 8: Check for Broken Object Cache

Some sites use Redis or Memcached.

If object cache is misconfigured, database queries may fail and Error Establishing a Database Connection may appear

Temporarily disable object cache by renaming:

wp-content/object-cache.php

Then reload the site.

Step 9: Fix Database Errors After Migration

After migrating a site, database details often change, and the Error Establishing a Database Connection issue may arise

Common mistake:

• old credentials left in wp-config.php

Make sure:

• database name matches the new server
• user has permissions
• host is correct

If the site worked before migration and broke after, this is usually the cause.

Step 10: Restore a Backup (Last Resort)

If the database is badly corrupted, restoring a backup may be the fastest fix.

Best practice:

• restore database only
• keep files unchanged if possible

Always restore on a staging site first if available.

How to Prevent This Error in the Future

Prevention is easier than recovery.

Use Reliable Hosting

Cheap hosting often causes database issues.

Managed WordPress hosting usually includes:

• optimized databases
• automatic backups
• monitoring

Schedule Regular Backups

Use daily backups for:

• database
• files

Test restores occasionally.

Optimize Database Regularly

You can schedule cleanup tasks:

wp_schedule_event( time(), 'weekly', 'db_optimization_event' );

Or use a trusted optimization plugin.

Monitor Server Health

Monitoring tools can alert you before failures happen.

Track:

• uptime
• CPU usage
• database response time

When to Get Professional Help

If:

• the Error Establishing a Database Connection error keeps returning
• you manage a business website
• downtime costs money

Professional help is often cheaper than repeated failures. Experienced WordPress developers can:

• diagnose server issues
• repair databases safely
• migrate sites to stable hosting
• optimize performance long-term

The “Error Establishing a Database Connection” message looks scary, but it is rarely permanent.

In most cases, it is caused by:

• incorrect credentials
• database corruption
• hosting limitations

By following the steps above in order, the issue can usually be fixed quickly and safely.

When the problem keeps returning, the real issue is often hosting quality or long-term maintenance.