Unable to upload files on the website after enabling Nginx

Symptoms

Attempting file uploads on the website doesn't complete or will fail, and the Nginx log contains an error similar to the following.

2025/06/19 08:58:05 [error] 419052#419052: *63 client intended to send too large body: 143058140 bytes, client: 203.0.113.2, server: domain.tld, request: "POST /upload.php HTTP/1.1", host: "domain.tld", referrer: "https://domain.tld/index.php"

Description 

Nginx has a limit on the body size. Uploads that exceed this limit will fail. The desired upload size must be set with the client_max_body_size option in the Nginx configuration.

Workaround

Please note that the following procedure assumes that the PHP INI configurations have already been adjusted to include the higher upload/post limits.

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Open /etc/nginx/ea-nginx/settings.json in your preferred text editor.
3. Change the client_max_body_size value to the desired size in megabytes.

    "client_max_body_size" : "500m"

4. Save the changes and exit the text editor.
5. Rebuild the Nginx configuration.

   /usr/local/cpanel/scripts/ea-nginx config --global

6. Verify that the change worked by checking the value in the configuration file.

   grep client_max_body_size /etc/nginx/conf.d/ea-nginx.conf

Additional resources

The Default Configuration of NGINX with Reverse Proxy: Configuration files