How to Fix a 504 Gateway Timeout Error

HTTP 504 Gateway Timeout means a front server — a proxy, load balancer or CDN — waited for the server behind it and received no reply before its timer ran out. Your browser did reach a server; the work behind that server did not finish in time.

It is not a crash and not a block. Extra seconds help a slow job that would have finished; they do not help a loop or an outside API that never answers. Find what is slow before raising any limit.

The shortest timer in the chain wins, so a 300-second PHP limit behind a 60-second proxy still returns a 504 at one minute.

If the page loads on another network, the 504 is on your path; if it fails on two networks, the site or its server is the cause. Test this first so you do not edit a server that is working.

1. Refresh once, then open the URL in a private window.
2. Try a phone on mobile data with any VPN or proxy turned off.
3. If it loads there, clear the cache and proxy settings on the device that failed, and stop.
4. If both fail, open cPanel → Metrics → Errors (or your server's error log), reload the URL once, and read the new line.
5. If the log is empty and a plain HTML file on the same account also returns 504, the delay is in the proxy or web server, not in one PHP script.

On a server you administer, raise the timer that the site actually passes through — proxy_read_timeout or fastcgi_read_timeout in Nginx, Timeout and ProxyTimeout in Apache, and request_terminate_timeout in the PHP-FPM pool — then test the config before reloading. Shared hosting does not expose these files.

# Nginx proxying to an app (Node, Python, another server)
location / {
    proxy_pass http://127.0.0.1:3000;
    proxy_read_timeout 300s;
}

# Nginx with PHP-FPM (proxy_read_timeout does not apply to FastCGI)
location ~ \.php$ {
    fastcgi_pass unix:/run/php/php-fpm.sock;
    fastcgi_read_timeout 300s;
}

# Apache (httpd.conf or the vhost)
Timeout 300
ProxyTimeout 300

# PHP-FPM pool file, e.g. /etc/php/8.3/fpm/pool.d/www.conf
request_terminate_timeout = 300

Run sudo nginx -t or sudo apachectl configtest and reload only if the test passes; restart PHP-FPM after editing its pool. Adjust the socket path and PHP version to match your server. A KVM VPS gives you access to all of these files.

A Cloudflare-branded 504 means Cloudflare's edge got no response from your origin, while error 524 means the connection opened but the origin took longer than Cloudflare's 100-second limit to reply. In both cases the slow part is your server, not Cloudflare.

To confirm, pause the Cloudflare proxy for that hostname (grey cloud) and load the site directly. If it loads quickly, look at the connection between Cloudflare and the origin, such as a firewall blocking Cloudflare's IP ranges. If the origin still times out, return to the log and the PHP limits. Turn the proxy back on after the test. Long reports or exports that need more than 100 seconds should run in the background and email the result.