The 10 Most Common WordPress Errors and How to Fix Them in 2026

WordPress: Powerful But Error-Prone

WordPress powers over 40% of websites worldwide, but that popularity comes at a price: frequent errors that can take your site offline, scare away visitors, and cost you sales. If you've ever seen a white screen where your website should be, you know exactly what we're talking about.

In this guide, we cover the 10 most common WordPress errors in 2026, their causes, and how to fix them step by step. At the end, we'll show you why more and more businesses are migrating to custom-built solutions to eliminate these problems at the root.

1. White Screen of Death (WSOD)

What it is

Your site displays a completely blank white page with no errors or messages. It's one of the most frustrating issues because it gives you zero clues about what went wrong.

Main causes

• Incompatible or corrupted plugin
• Theme with PHP code errors
• PHP memory limit exhausted
• Corrupted .htaccess file

How to fix it

1. Enable debug mode by adding define('WP_DEBUG', true); to wp-config.php
2. Deactivate all plugins by renaming the /wp-content/plugins/ folder
3. Switch to the default theme by renaming your active theme in /wp-content/themes/
4. Increase PHP memory limit to 256M in wp-config.php

2. Error 500 Internal Server Error

What it is

The server cannot process the request. It's a generic server error that can have multiple causes.

Main causes

• Corrupted .htaccess file
• Insufficient PHP memory limit
• Faulty plugins or themes
• Incorrect file permissions

How to fix it

1. Rename the .htaccess file and regenerate a new one from Settings → Permalinks
2. Increase PHP memory limit: define('WP_MEMORY_LIMIT', '256M');
3. Deactivate plugins one by one to identify the conflict
4. Verify permissions are 755 for folders and 644 for files

3. Error Establishing a Database Connection

What it is

WordPress cannot connect to the MySQL database. Your site becomes completely inaccessible.

Main causes

• Incorrect credentials in wp-config.php
• Database server down
• Corrupted database
• Damaged WordPress files

How to fix it

1. Verify credentials (DB_NAME, DB_USER, DB_PASSWORD, DB_HOST) in wp-config.php
2. Contact your hosting provider to check MySQL server status
3. Try repairing the database by adding define('WP_ALLOW_REPAIR', true); and visiting /wp-admin/maint/repair.php
4. Reinstall WordPress core files via FTP

4. 404 Errors After Changing Permalinks

What it is

All pages except the homepage return a 404 error, usually after changing the permalink structure.

Main causes

• .htaccess file didn't update correctly
• mod_rewrite module not enabled on Apache
• Conflict with server rules

How to fix it

1. Go to Settings → Permalinks and click "Save Changes" without modifying anything
2. If that doesn't work, manually edit .htaccess with WordPress rewrite rules
3. Contact your hosting to verify mod_rewrite is active

5. Memory Exhausted Error (PHP Fatal Error)

What it is

You see a message like: Fatal error: Allowed memory size of X bytes exhausted. It means PHP ran out of memory to run WordPress.

Main causes

• Too many active plugins consuming memory
• Heavy theme with extensive functionality
• Inefficient database queries
• Very low hosting memory limit

How to fix it

1. Add to wp-config.php: define('WP_MEMORY_LIMIT', '256M');
2. Modify php.ini: memory_limit = 256M
3. Optimize by reducing unnecessary plugins
4. Consider hosting with more resources

6. "Briefly Unavailable for Scheduled Maintenance"

What it is

WordPress displays this message during updates. The problem is when it gets stuck and the site doesn't return to normal.

Main causes

• Interrupted update (closing browser during update)
• Plugin conflict during the update
• Server timeout

How to fix it

1. Access the root of your WordPress installation via FTP
2. Delete the .maintenance file
3. Your site should return to normal immediately
4. If the problem persists, update manually via FTP

7. Syntax Errors After Editing functions.php

What it is

A PHP syntax error that makes your site inaccessible, usually after adding custom code to the theme's functions.php file.

Main causes

• Missing semicolon, parenthesis, or bracket
• PHP code incompatible with the server version
• Copy-pasting code with invisible characters

How to fix it

1. Access the functions.php file via FTP or hosting file manager
2. Locate the error line mentioned in the message
3. Fix the syntax or remove the code you added
4. Use a child theme to avoid losing changes during updates

8. Upload File Size Limit Exceeded

What it is

WordPress won't let you upload files that exceed the limit set by PHP, showing an error when trying to upload images or documents.

Main causes

• Restrictive PHP configuration on hosting
• Limits in php.ini, .htaccess, or wp-config.php

How to fix it

1. Modify php.ini: upload_max_filesize = 64M and post_max_size = 64M
2. Or add to .htaccess: php_value upload_max_filesize 64M
3. Or use a plugin like "Increase Maximum Upload File Size"
4. If nothing works, contact your hosting provider

9. Sidebar Appearing Below Content

What it is

Instead of appearing next to the main content, the sidebar drops below it, breaking your site's layout.

Main causes

• Unclosed HTML in a post or page (an unclosed <div> tag)
• Theme CSS with incorrect widths
• Plugin injecting faulty HTML
• Content too wide for the content area

How to fix it

1. Check the last published content for unclosed HTML tags
2. Use the browser inspector to verify column widths
3. Deactivate recent plugins to detect conflicts
4. Verify that the theme CSS hasn't been incorrectly modified

10. Login Page Redirect Loop

What it is

When trying to access the admin panel, WordPress constantly redirects you to the login page without letting you in.

Main causes

• Corrupted browser cookies
• WordPress URLs configured incorrectly
• Conflicting cache or security plugin
• wp-config.php with incorrect URLs

How to fix it

1. Clear browser cookies and cache
2. Verify in wp-config.php that WP_HOME and WP_SITEURL are correct
3. Rename the plugins folder via FTP to deactivate them
4. Delete the object-cache.php file from /wp-content/

The Repeating Pattern: Why Does WordPress Fail So Much?

If you look at all 10 errors above, there's a clear pattern:

These problems are inherent to WordPress's architecture. No matter how many times you fix them, they'll come back with the next update, the next plugin, or the next traffic spike.

Tired of Fixing WordPress Errors?

There's an alternative: a custom-built website that eliminates these vulnerabilities at the root.

At AvilaDev, we develop websites with modern technology (Next.js, React, TypeScript) that offer:

• Zero plugin dependency — every feature is built into the code, no conflicts
• Superior performance — pages that load in under 1 second with static generation
• Robust security — no plugin vulnerabilities or wp-admin attacks
• Real scalability — handles thousands of visits without touching server config
• Minimal maintenance — no plugin, theme, or core updates breaking your site

How many hours have you lost fixing WordPress errors this year? That time could be generating sales with a site that simply works.

Calculate the cost of your professional website →

Request a free consultation →

You might also like: WordPress Plugins: Conflicts, Vulnerabilities, and When to Migrate