Error Establishing Database Connection WordPress

If you’ve ever opened your website only to be greeted by the message “Error establishing a database connection WordPress”, you’re not alone. This is one of the most common — and most confusing — errors WordPress users encounter.

良いニュースですか?
This error usually means WordPress can’t talk to its database — not that your site is permanently broken.

In this guide, we’ll explain what this error really means, why it happens, and how to troubleshoot it step by step, using plain language instead of technical jargon. Whether you run a business site, blog, or cross-border eCommerce store, this article will help you understand the issue and regain control.

What Does “Error Establishing a Database Connection” Mean?

At its core, WordPress works like a messenger.

When someone visits your site, WordPress:

1. Connects to the database
2. Fetches content (posts, pages, products, settings)
3. Displays everything using your theme

If WordPress cannot reach the database, it has nothing to display — so it shows the error instead.

In other words:

WordPress itself is running, but the database connection has failed.

This usually points to a configuration problem, server issue, or database outage, not a broken theme or page builder.

How WordPress Connects to the Database (Simple Explanation)

To understand the problem, it helps to know how WordPress connects to its database.

WordPress stores critical connection details inside a file called:

wp-config.php

This file contains:

• データベース名
• Database username
• Database password
• Database host (server address)

When even one of these values is wrong — or the database server is unavailable — WordPress cannot connect.

Most Common Causes of This Error

Let’s break down the real-world reasons this error appears.

1. Incorrect Database Credentials

This is the most common cause.

If the database name, username, or password in wp-config.php doesn’t match what’s on your server, the connection fails.

This often happens when:

• Migrating a site to a new host
• Restoring a backup
• Changing database passwords
• Setting up a staging or development site

Even a single typo can trigger the error.

2. Corrupted WordPress Database

Databases can become corrupted due to:

• Server crashes
• Plugin conflicts
• 更新に失敗しました
• Malware or brute-force attacks

In these cases, WordPress may reach the database server but fail to read the data properly.

3. Database Server Is Down

Sometimes the issue isn’t WordPress at all.

If the database server (MySQL/MariaDB) is offline or overloaded, WordPress cannot connect — even with correct credentials.

This often happens on:

• 共有ホスティング
• Cheap VPS setups
• Servers under traffic spikes

4. Corrupted Core WordPress Files

Less common, but still possible.

If core WordPress files are damaged or incomplete (often due to failed updates or manual uploads), WordPress may not initialize correctly.

5. Hosting Environment Problems

Hosting issues can include:

• Insufficient PHP memory
• Disabled MySQL services
• Incorrect server permissions
• Misconfigured firewall rules

These problems are especially common on DIY servers or poorly optimized hosting environments.

Step-by-Step: How to Fix the Error

Let’s go through practical troubleshooting steps — from simplest to more advanced.

Step 1: Check Your Database Credentials

開ける wp-config.php and look for these lines:

define('DB_NAME', 'database_name_here');
define('DB_USER', 'username_here');
define('DB_PASSWORD', 'password_here');
define('DB_HOST', 'localhost');

Make sure they match exactly what your hosting provider shows in:

• cパネル
• プレスク
• クラウドパネル
• Hosting dashboard

Common mistakes:

• Extra spaces
• Wrong database name after migration
• Using old credentials

If you recently changed hosts, this step alone often fixes the issue.

Step 2: Test Database Connection Manually

If credentials look correct, test whether the database itself is reachable.

Most hosts provide:

• phpMyAdmin
• Adminer
• Database management panel

Try logging in using the same username and password.
If login fails, the problem is not WordPress — it’s the database or credentials.

Step 3: Repair a Corrupted Database

WordPress includes a built-in database repair tool.

Add this line to wp-config.php:

define('WP_ALLOW_REPAIR', true);

Then visit:

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

Run the repair process.

⚠️ Important:
Remove the line after repairing — leaving it active is a security risk.

Step 4: Check Your Database Host

Most sites use:

DB_HOST = localhost

But some hosts require:

• A custom IP
• A different hostname
• Internal network address

If you’re unsure, ask your host or check their documentation.

Using the wrong database host will trigger this error even with correct credentials.

Step 5: Restart Database Server (Advanced)

If you manage your own server (VPS or dedicated), your database service may be down.

Common services:

• MySQL
• MariaDB

Restarting the service often resolves temporary outages caused by memory exhaustion or crashes.

If you’re on managed hosting, contact support instead.

Step 6: Check for Plugin or Theme Conflicts

Sometimes a plugin:

• Sends malformed queries
• Overloads the database
• Breaks the connection under traffic

If possible:

1. 名前を変更する プラグイン folder temporarily
2. Check if the site loads
3. Restore plugins one by one

This helps identify problematic plugins.

Step 7: Reupload Core WordPress Files

If nothing else works, corrupted core files may be the issue.

Upload fresh copies of:

• wp-admin
• wp-includes

⚠️ Do ない overwrite wp-コンテンツ または wp-config.php.

This step fixes issues caused by incomplete updates or file corruption.

How to Prevent This Error in the Future

Prevention matters just as much as fixing the issue.

Best Practices:

• Use reliable hosting
• Avoid excessive low-quality plugins
• Keep WordPress, themes, and plugins updated
• Set up automated backups
• Monitor server resource usage
• Secure your site against brute-force attacks

For business and eCommerce sites, these steps are critical — downtime directly impacts revenue and trust.

Why This Error Matters for Business Websites

If your site shows a database error:

• Customers can’t browse
• Search engines may deindex pages
• Ads traffic is wasted
• Brand trust drops instantly

For cross-border brands, the impact is even larger due to:

• Multiple time zones
• Paid traffic campaigns
• International customers

This is why database stability and hosting architecture are not “just technical details” — they’re business fundamentals.

最後に

The “Error establishing database connection WordPress” message looks intimidating, but it usually points to a clear, fixable issue.

In most cases:

• Credentials are incorrect
• The database needs repair
• The server is under stress

Understanding the logic behind the error empowers you to fix it faster — or communicate clearly with your hosting provider or technical team.

AIRSANGがどのように役立つか

で エアサン, 弊社は越境ウェブサイトを専門としており、, ワードプレス architecture, and performance-focused design — not just how a site looks, but how it works under real traffic conditions.

私たちはブランドを支援します:

• Build stable WordPress infrastructures
• Optimize databases and hosting setups
• コンバージョン重視のウェブサイトをデザインする
• Prevent critical downtime issues before they happen

If you’re running — or planning — an international website and want reliability, scalability, and professional execution, エアサン お手伝いいたします。.

Feel free to reach out if you want your WordPress site built the right way from day one.