Edit the Nginx Configuration File

Open the Nginx configuration file for your site. This is typically located in  /etc/nginx/nginx.conf.

Increase the Buffer Size

fastcgi_buffers 16 16k;
fastcgi_buffer_size 32k;

Example Code

location ~ \.php$ {
include fastcgi_params;
fastcgi_pass 172.26.0.6:9000;
fastcgi_buffers 16 16k;
fastcgi_buffer_size 32k;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}

Test the Nginx Configuration

After making changes, test the Nginx configuration to ensure there are no syntax errors:

sudo nginx -t

Reload Nginx

If the configuration test is successful, reload Nginx to apply the changes:

sudo systemctl reload nginx