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How to Fix 504 Gateway Timeout Error in Nginx with PHP-FPM (Quickly)

Read Time: 4 min Updated: 2026-07-26

Quick Diagnostics

The 504 Gateway Timeout error occurs when Nginx acts as a reverse proxy in front of a backend server (such as PHP-FPM) and the backend fails to respond within the configured timeout limit.

🔍 Quick Diagnostics

Symptom Root Cause Solution
HTTP 504 Gateway Timeout when executing long-running PHP scripts Nginx or PHP-FPM closes connection as request execution exceeds fastcgi_read_timeout or max_execution_time Increase timeout values in Nginx configuration and php.ini / FPM pool configuration

🚀 How to Fix the Error Step-by-Step

Step 1: Increase Timeouts in Nginx Configuration

Open your site's Nginx configuration file (e.g., /etc/nginx/sites-available/default or /etc/nginx/conf.d/default.conf):

NGINX 
server {
    listen 80;
    server_name example.com;

    location ~ \.php$ {
        include fastcgi_params;
        fastcgi_pass unix:/run/php/php8.2-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

        # Increase FastCGI timeout limits
        fastcgi_connect_timeout 300s;
        fastcgi_send_timeout 300s;
        fastcgi_read_timeout 300s;
    }
}

Step 2: Configure Execution Limits in PHP-FPM

Adjust the execution time directives in your php.ini file (/etc/php/8.2/fpm/php.ini):

INI 
max_execution_time = 300
max_input_time = 300
memory_limit = 256M

Additionally, update your PHP-FPM pool configuration file (/etc/php/8.2/fpm/pool.d/www.conf):

INI 
request_terminate_timeout = 300s

Step 3: Validate and Restart Services

Test the Nginx configuration syntax before applying changes:

BASH 
sudo nginx -t

If the test is successful, restart Nginx and PHP-FPM:

BASH 
sudo systemctl restart php8.2-fpm
sudo systemctl restart nginx

Prevention Advice

Recommended security practices:

  • Offload Heavy Tasks to Background Queues: Use queue managers like Redis with Celery/Supervisor or Laravel Queues for long tasks like PDF generation or image processing.
  • Monitor Slow Logs: Enable request_slowlog_timeout in PHP-FPM to log scripts and database queries that slow down request handling.
  • Optimize Database Queries: Index high-frequency database tables in MySQL/PostgreSQL to prevent backend locks during HTTP requests.