How to Fix the “wp-admin/admin-ajax.php 403 Forbidden” Error in WordPress (Complete 2026 Guide)

The dreaded 403 Forbidden error for your admin-ajax.php file is one of those WordPress issues that can bring your site to a grinding halt. One moment everything is working fine, and the next, your live product filters stop working, your “Add to Cart” buttons become unresponsive, your forms refuse to submit, and your admin dashboard starts acting strangely. If you’re seeing a “403 Forbidden” error when trying to access yoursite.com/wp-admin/admin-ajax.php, you’re in the right place.

This comprehensive guide will walk you through exactly what this error means, why it’s so critical, and most importantly, provide you with a step-by-step troubleshooting methodology to fix it for good. We’ll cover everything from basic permission checks to advanced server configurations, ensuring you have a solution regardless of your technical skill level or hosting environment. If you’re feeling overwhelmed, remember that our team offers Emergency WordPress Support for immediate, professional assistance.

What is admin-ajax.php and Why Does a 403 Error Break Your Site?

Before we dive into fixes, let’s understand the problem. The admin-ajax.php file is the backbone of WordPress’s AJAX (Asynchronous JavaScript and XML) functionality. In simpler terms, it’s the behind-the-scenes worker that handles requests without requiring a full page reload. This same mechanism powers many features that can break in various ways, similar to issues covered in our guide on WooCommerce Cart Not Updating.

When you interact with dynamic elements on your WordPress site, here’s what typically happens:

1. You click a “Load More” button, submit a contact form, or add a product to your cart

2. JavaScript sends a request to /wp-admin/admin-ajax.php

3. The file processes the request, talks to the database if needed, and returns data

4. JavaScript updates the page content dynamically

A 403 Forbidden error means the server understood the request but refuses to authorize it. Essentially, something is blocking access to this critical file. When this happens, any feature relying on AJAX stops working. This can include:

• WooCommerce add-to-cart functionality (related to issues in WooCommerce Stock Not Updating After Orders)

• Live search suggestions

• Contact form submissions (similar to problems in WooCommerce Not Sending Emails)

• Infinite scroll or load more buttons

• Dashboard updates without refresh

• Plugin settings that save via AJAX

• Theme customization previews

The error can manifest in different ways: sometimes as a visible 403 error page, sometimes as silent failures in your browser’s developer console, and sometimes as broken functionality with no obvious error messages—not unlike the mysterious WordPress White Screen After Update issue many site owners face.

Step-by-Step Troubleshooting Methodology

Follow these steps in order. We’ll start with the simplest, most common solutions and progress to more advanced fixes. Remember to always have a reliable backup solution in place before making significant changes.

Step 1: Basic Preliminary Checks

Before making any changes, let’s rule out temporary issues. These initial checks are similar to what we recommend when troubleshooting WordPress Showing Old Content After Updates.

Clear All Caches: Start by clearing every cache layer:

• Your WordPress caching plugin (if using one)

• Your browser cache (Ctrl+F5 or Cmd+Shift+R for hard refresh)

• Server-level cache (if your host provides one, like Varnish)

• CDN cache (Cloudflare, StackPath, etc.)

• Object cache (Redis, Memcached) if enabled

Check Browser Console: Open your browser’s developer tools (F12), go to the Console tab, and try to trigger the broken functionality. Look for 403 errors mentioning admin-ajax.php. Note the exact error message and status code. This same debugging approach helps with WordPress CSS Not Loading issues.

Test in Different Environments: Try accessing your site from:

• A different browser (Chrome, Firefox, Edge)

• An incognito/private browsing window

• A different network (switch off WiFi to use mobile data)

• This helps determine if the issue is localized to your setup, much like when diagnosing WooCommerce Shipping Zones Not Detecting Customers.

Step 2: Check File Permissions (The Most Common Fix)

Incorrect file permissions are the leading cause of 403 errors. The server needs to be able to read and execute the admin-ajax.php file, but not everyone should have write access. Permission issues often cause multiple problems, similar to Error Writing File on WordPress Upload.

Correct Permissions for WordPress Files:

• Folders/directories: 755 (or 750 on some strict hosts)

• Files: 644 (or 640 on some strict hosts)

• wp-admin/admin-ajax.php specifically: 644

How to Check and Fix Permissions via FTP/SFTP or File Manager:

1. Connect to your site using an FTP client like FileZilla or your hosting control panel’s File Manager.

2. Navigate to the /wp-admin/ directory.

3. Find admin-ajax.php and check its current permissions.

4. If incorrect, right-click the file and select “File Permissions” or “CHMOD.”

5. Change the numeric value to 644.

6. Apply the changes.

Important: Also check the permissions of the parent wp-admin directory (should be 755) and the main WordPress root files. Incorrect permissions can also lead to issues like WordPress Media Library Not Showing Images.

If you have SSH access, you can fix permissions with these commands:

# Fix file permissions
find /path/to/your/wordpress/install/ -type f -exec chmod 644 {} \;

# Fix directory permissions  
find /path/to/your/wordpress/install/ -type d -exec chmod 755 {} \;

# Specifically fix admin-ajax.php if needed
chmod 644 /path/to/your/wordpress/install/wp-admin/admin-ajax.php

Warning: Be cautious with recursive permission changes. If you’re on shared hosting, check with your host first, as they may have specific requirements. Some security-conscious setups recommend 640 for files and 750 for directories. For comprehensive security guidance, see our guide on How to Secure wp-config.php.

Step 3: Disable Security Plugins and Firewalls Temporarily

Security plugins and server firewalls are designed to block suspicious requests, but they can sometimes be overzealous and block legitimate AJAX requests. This over-protection can manifest in various ways, similar to XML-RPC Attacks protection gone wrong.

Temporarily Disable WordPress Security Plugins:

1. Go to Plugins → Installed Plugins

2. Deactivate security plugins like Wordfence, iThemes Security, Sucuri, MalCare, etc.

3. Test if the AJAX functionality works

4. Remember to reactivate them after testing

If the error disappears after disabling a security plugin, you’ll need to reconfigure it. Check the plugin’s settings for:

• Firewall rules that might block AJAX

• Rate limiting that’s too aggressive

• Country blocking that might affect your IP

• Learning mode vs. enabled mode in the firewall

Temporarily Disable Server-Level Firewalls:
If you have access to server tools like CSF (ConfigServer Security & Firewall) or similar, check their logs for blocks related to admin-ajax.php. You might need to whitelist the request pattern. For more on server-level security, check our comparison of Best WordPress Security Plugins.

For those using Cloudflare, check these settings:

• Firewall Rules: Look for rules blocking POST requests or specific paths

• Rate Limiting: Might be triggering on AJAX requests

• Under Attack Mode: This can sometimes interfere with AJAX

• WAF (Web Application Firewall): Check for rules blocking the admin-ajax.php path

Step 4: Check and Modify .htaccess Rules

An incorrectly configured .htaccess file can block access to specific files or directories. The .htaccess file in your WordPress root directory controls Apache server rules. Problems here can also cause issues like WordPress Redirecting HTTP to HTTPS Incorrectly.

First, make a backup of your current .htaccess file before making any changes. Knowing how to Restore a WordPress Site from Backup is crucial when making such changes.

Common problematic .htaccess rules:

1. Overly restrictive directory rules: Rules that block access to /wp-admin/ entirely

2. IP blocking rules: That might be blocking legitimate requests

3. Hotlink protection: That might be interfering with internal requests

4. Security plugins’ rules: That might be too aggressive

Temporary test: Rename your .htaccess file to .htaccess_backup temporarily. If the 403 error disappears, you know the problem is in your .htaccess file.

Standard WordPress .htaccess for reference:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

If you need to add specific rules to allow admin-ajax.php, you can add this before the WordPress rules:

<Files "admin-ajax.php">
    Order Allow,Deny
    Allow from all
    Satisfy Any
</Files>

For Nginx users: If you’re on an Nginx server, you’ll need to check your server configuration file (usually in /etc/nginx/sites-available/). Look for rules that might be blocking access to the wp-admin directory and ensure there’s a location block properly handling PHP files. Server configuration issues can also affect Time to First Byte (TTFB) performance.

Step 5: Investigate ModSecurity Rules

ModSecurity is a web application firewall (WAF) that runs on Apache servers. It’s powerful for security but notorious for false positives that block legitimate requests like AJAX calls. Similar over-blocking can happen with other security measures, as discussed in our guide on Error 429 Too Many Requests.

How to check if ModSecurity is causing the issue:

1. Check server error logs: Look for entries mentioning ModSecurity or rule IDs

2. Temporarily disable ModSecurity: If you have cPanel/WHM access, you might find ModSecurity under “Security Center”

3. Check for .htaccess directives: Some hosts allow ModSecurity rules in .htaccess

If you confirm ModSecurity is the culprit:

• Contact your hosting provider with the specific rule ID from your error logs

• Ask them to whitelist the rule for your site

• Alternatively, they might suggest adding an exception in your .htaccess:

<IfModule mod_security2.c>
  SecRuleRemoveById [RULE_ID_NUMBER]
</IfModule>

Replace [RULE_ID_NUMBER] with the actual rule ID from your logs.

Step 6: Check PHP and Server Configuration

Sometimes the issue stems from PHP configuration or server settings that affect how requests are processed. Configuration problems can cascade into multiple issues, similar to those covered in Allowed Memory Size Exhausted.

Increase PHP Memory Limit: AJAX requests, especially those involving plugins like WooCommerce, can require more memory. Add this to your wp-config.php file:

define('WP_MEMORY_LIMIT', '256M');
define('WP_MAX_MEMORY_LIMIT', '512M');

Adjust PHP Execution Time: AJAX requests might be timing out. Increase the limit in your wp-config.php:

set_time_limit(300); // 300 seconds = 5 minutes

Check for PHP Handler Issues: Some PHP handlers (like suPHP) have strict permission requirements. If you recently changed PHP versions or handlers, this could be the issue. Contact your host to ensure your PHP handler is compatible with your permission setup. PHP issues can also affect MySQL Too Many Connections.

Verify open_basedir Restrictions: If open_basedir is enabled in your PHP configuration, it might be restricting access to necessary directories. Check your PHP error logs for open_basedir violation messages. This typically needs to be adjusted by your hosting provider.

Step 7: Check for Plugin and Theme Conflicts

A conflicting plugin or theme is a common cause of AJAX issues. This is particularly true after updates. Plugin conflicts are a frequent culprit behind many WordPress problems, as detailed in our guide on Top 15 Common WordPress Issues.

Perform a Conflict Test:

1. Switch to a default theme: Temporarily activate Twenty Twenty-Four or similar default WordPress theme

2. Test AJAX functionality: Check if the 403 error persists

3. If fixed: Your theme is the culprit. Contact the theme developer or check theme settings related to AJAX/security

Plugin Conflict Test:

1. Disable all plugins: You can do this via FTP by renaming the plugins folder if you can’t access wp-admin

2. Test if AJAX works: With all plugins disabled

3. Re-enable plugins one by one: Testing after each activation

4. Identify the culprit: When the error returns, you’ve found the problematic plugin

Important: If you cannot access wp-admin due to the error, use one of these methods to disable plugins:

Via FTP/File Manager:

1. Navigate to /wp-content/

2. Rename the plugins folder to plugins_deactivated

3. This will disable all plugins

4. Test your site

5. Rename back to plugins and disable plugins individually

Via Database (if you have phpMyAdmin access):

1. Access your database via phpMyAdmin

2. Find the wp_options table (prefix might be different)

3. Look for the active_plugins row in the option_name column

4. Edit the option_value field and change it to: a:0:{}

5. This deactivates all plugins

For detailed guidance on managing plugins without admin access, see our guide on How to Disable All WordPress Plugins Without WP Admin Access. Plugin issues can also affect other areas like WooCommerce Analytics Not Tracking.

Step 8: Check User Roles and Capabilities

In some cases, the 403 error might be related to user capabilities rather than file permissions. This is especially true if:

• The error only happens for logged-out users

• The error only happens for certain user roles

• You recently changed capability settings

Test with different user states:

1. Test AJAX functionality while logged out

2. Test while logged in as an administrator

3. Test while logged in as a subscriber/customer

If the error only occurs for non-logged-in users, the issue might be with:

• AJAX actions requiring authentication: Some plugins incorrectly mark AJAX actions as requiring user authentication

• Security plugins blocking non-authenticated requests: Some security configurations are overly aggressive

Check your theme’s functions.php for code that modifies AJAX behavior. Look for lines like:

add_action('wp_ajax_my_action', 'my_function'); // Requires login
add_action('wp_ajax_nopriv_my_action', 'my_function'); // Doesn't require login

If a plugin only registers the wp_ajax_ hook (with authentication) but not the wp_ajax_nopriv_ hook (without authentication), logged-out users will get permission errors. User role issues can also affect WooCommerce Orders Not Showing in Admin.

Step 9: Examine Server Error Logs

Your server error logs often contain the exact reason for a 403 error, which can save hours of guesswork. Log examination is a crucial skill for resolving many WordPress issues, including 500 Internal Server Error.

How to access error logs:

• cPanel: Look for “Error Log” or “Metrics → Errors”

• Direct server access: Usually /var/log/apache2/error.log or /var/log/nginx/error.log

• Via .htaccess: Add php_flag log_errors on and php_value error_log /path/to/your/error.log to log PHP errors

• WordPress debug log: Enable WordPress debugging by adding to wp-config.php:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

This will create a debug.log file in /wp-content/ with detailed error information. For more debugging techniques, see How to Enable WordPress Debug Mode.

What to look for in logs:

• “Permission denied” messages

• “Client denied by server configuration”

• ModSecurity rule triggers

• PHP warnings or fatal errors

• Specific file paths that are being blocked

Step 10: Verify Server Configuration Files

For users with VPS or dedicated server access, server configuration files might be causing the issue. Server configuration affects many aspects of WordPress performance, including Core Web Vitals.

Apache users: Check:

1. /etc/apache2/apache2.conf or /etc/httpd/conf/httpd.conf

2. Virtual host files in /etc/apache2/sites-available/

3. Look for Deny directives or restrictive Directory blocks

Nginx users: Check:

1. Server block configuration files

2. Look for deny directives or incorrect location blocks

3. Ensure PHP is properly passed to the PHP processor

A common issue is that the server configuration has a rule blocking access to the wp-admin directory entirely. You might need to add an exception for admin-ajax.php.

Step 11: Check for Malware and File Integrity

Sometimes, the 403 error is actually a security feature blocking a compromised file. If your admin-ajax.php file has been modified by malware, security tools might block it. Security is paramount, as covered in our guide on Stop Brute-Force Hacks.

Verify file integrity:

1. Download a fresh copy of WordPress from wordpress.org

2. Compare the admin-ajax.php file with your current one

3. Look for unexpected code, especially at the beginning or end of the file

4. Check file size and modification date

Use security scanners:

• Run a malware scan using a plugin like Wordfence or MalCare

• Use your hosting provider’s security tools

• Check for suspicious code in all WordPress core files

If you find malware, follow our comprehensive guide on How to Clean a Hacked WordPress Site Without Losing SEO. Security issues can also manifest as WordPress Site Keeps Refreshing problems.

Step 12: Advanced Debugging with WordPress Hooks

For developers or advanced users, WordPress provides hooks to debug AJAX requests specifically. Advanced debugging can help with complex issues like those covered in WordPress REST API Authentication Errors.

Add debugging to AJAX requests:

add_action('wp_ajax_nopriv_debug_ajax', 'debug_ajax_request');
add_action('wp_ajax_debug_ajax', 'debug_ajax_request');

function debug_ajax_request() {
    // Log all incoming data
    error_log('AJAX Request: ' . print_r($_REQUEST, true));
    
    // Check user capabilities
    if(is_user_logged_in()) {
        error_log('User is logged in');
    } else {
        error_log('User is not logged in');
    }
    
    // Test response
    wp_send_json_success(array('message' => 'AJAX test successful'));
}

Check what AJAX actions are being called:
Add this to your theme’s functions.php to log all AJAX actions:

add_action('admin_init', 'log_ajax_actions');
function log_ajax_actions() {
    if(defined('DOING_AJAX') && DOING_AJAX) {
        error_log('AJAX Action: ' . $_REQUEST['action']);
    }
}

Prevention: How to Stop This Error from Happening Again

Once you’ve fixed the 403 error, take these steps to prevent recurrence. Prevention is part of a good WordPress Maintenance Checklist.

1. Regular Backups: Ensure you have daily backups. See our guide on Backup WordPress to Google Drive for automated solutions.

2. Staging Environment: Always test updates on a staging site first. Learn how in How to Create a Staging Site in WordPress.

3. Update Strategy: Keep WordPress core, themes, and plugins updated, but don’t update everything at once. Space out updates and monitor for issues. Consider Automatic Updates for WordPress with proper safeguards.

4. Security Best Practices: Implement proper security measures without being overly restrictive. Our guide on 10 Best Security Plugins for WordPress can help. Also consider WordPress Two-Factor Authentication.

5. Monitor Error Logs: Regularly check error logs for early warning signs. Consider using a monitoring service.

6. Document Changes: Keep a record of any server, plugin, or theme changes that might affect AJAX functionality.

7. Optimize AJAX Usage: Reduce unnecessary AJAX calls and optimize existing ones. For related performance issues, see How to Fix High Admin-Ajax Usage in WordPress. Also optimize other areas like WordPress Database Performance.

When to Contact Your Hosting Provider

If you’ve tried all the above steps and still face the 403 error, it’s time to contact your hosting provider. Before reaching out, ensure you’ve checked common issues like those in our guide on Error Establishing a Database Connection.

Provide them with:

1. Exact error messages from your logs

2. Steps you’ve already tried

3. When the issue started

4. Any recent changes to your site

Specific issues your host can help with:

• ModSecurity rule whitelisting

• Server configuration adjustments

• PHP handler issues

• File permission guidance specific to their environment

• Firewall adjustments

If you’re consistently having hosting-related issues, consider following our guide on Move Your WordPress Site to a New Host.

Frequently Asked Questions (FAQs)

What does a 403 Forbidden error mean for admin-ajax.php?
A 403 Forbidden error for admin-ajax.php means your server is blocking access to this critical WordPress file. This file handles AJAX requests for dynamic functionality like forms, shopping carts, and live updates. When blocked, these features stop working. Similar access issues can occur with WordPress Sitemap Not Working.

Can a caching plugin cause admin-ajax.php 403 errors?
Yes, caching plugins can sometimes cause 403 errors if they cache AJAX responses or interfere with POST requests. Some caching plugins have overly aggressive settings that block what they perceive as suspicious requests to admin-ajax.php. Try disabling your caching plugin temporarily to test if it’s the cause. For caching plugin options, see our comparison of Best Caching Plugins for WordPress.

How do I know if ModSecurity is causing the 403 error?
Check your server error logs for entries containing “ModSecurity” or specific rule IDs. You can also temporarily disable ModSecurity (if you have access) or contact your hosting provider to check ModSecurity logs. Many hosts use ModSecurity rules that can sometimes block legitimate AJAX requests. Similar blocking can occur with other security measures discussed in Limit WordPress Login Attempts.

Why does the 403 error only happen for logged-out users?
This usually indicates that the AJAX action is only registered for logged-in users (using wp_ajax_ hook) but not for logged-out users (missing wp_ajax_nopriv_ hook). Some security plugins also treat AJAX requests from non-logged-in users as suspicious and block them. User-specific issues can also affect WordPress Auto-Creating Spam Users.

Is it safe to change permissions on admin-ajax.php to 777 to fix the error?
No, never set permissions to 777. This gives everyone read, write, and execute permissions, creating a severe security risk. Use 644 for files and 755 for directories instead. If 644 doesn’t work, check with your hosting provider as some environments require different settings. Proper permissions are crucial for security, as emphasized in WordPress Database Corruption Prevention.

Can Cloudflare cause admin-ajax.php 403 errors?
Yes, Cloudflare’s firewall, rate limiting, or security rules can sometimes block legitimate requests to admin-ajax.php. Check your Cloudflare firewall rules, WAF settings, and rate limiting configurations. You might need to create a rule to allow requests to admin-ajax.php or whitelist it from certain security features. CDN issues can also affect Serving CSS/JS from a CDN.

How do I fix admin-ajax.php 403 errors on Nginx servers?
On Nginx, check your server block configuration for rules that might be blocking access to wp-admin or admin-ajax.php. Ensure PHP requests are properly passed to the PHP processor. You may need to add a specific location block for admin-ajax.php or adjust existing restrictions. Server optimization also affects First Input Delay (FID).

Will restoring from backup fix the admin-ajax.php 403 error?
It might, if the error was caused by recent changes to files, plugins, or themes. However, if the error is due to server configuration, permissions, or security settings, a restore won’t help. Always identify the root cause before restoring to ensure the issue doesn’t reoccur. For backup restoration, see Unknown Compression Method When Extracting Backups.

Can a recent WordPress update cause this error?
Yes, sometimes WordPress core updates can conflict with existing server configurations, security plugins, or custom code. If the error started after an update, try the conflict tests mentioned in this guide and check if any of your plugins or themes need updates for compatibility. Update issues can also cause WordPress Classic Editor Not Working.

What should I do if none of these solutions work?
If you’ve tried all solutions and still face the error, contact your hosting provider with all the troubleshooting steps you’ve attempted and error logs. The issue might be specific to your server configuration. As a last resort, consider migrating to a different host if the current one cannot resolve persistent server-level issues. For immediate professional help, consider our Emergency WordPress Support service.

Conclusion

The “wp-admin/admin-ajax.php 403 Forbidden” error can be frustrating, but it’s almost always fixable with methodical troubleshooting. Start with the simplest solutions like clearing caches and checking file permissions, then work your way through the more advanced fixes if needed. Many similar WordPress issues require systematic approaches, like those needed for Too Many Redirects Error.

Remember that prevention is key. Regular maintenance, proper backup strategies, and careful updating can help prevent this and other WordPress errors. Implementing an Ultimate WordPress SEO Checklist alongside technical maintenance ensures both functionality and visibility.

If you’re dealing with other WordPress issues, check out our comprehensive guide on Top 15 Common WordPress Issues and How to Fix Them for solutions to the most frequent problems. For ongoing performance, consider our guides on Optimize WordPress for Mobile Speed and Optimize WordPress for Largest Contentful Paint (LCP).

By understanding what causes this error and how to fix it, you’re not just solving an immediate problem—you’re becoming more proficient at managing and maintaining your WordPress site for the long term. And remember, when you need immediate professional assistance, our Emergency WordPress Support team is always ready to help resolve any WordPress issue quickly and efficiently.