What specific Nginx configuration settings might contribute to a 500 error?

Incorrect `proxy_pass` directives, improper handling of timeouts (`proxy_connect_timeout`, `proxy_read_timeout`, `proxy_send_timeout`), or issues with `fastcgi_pass` (if using PHP-FPM) can cause 500 errors. Ensure the upstream server address and port are correct in your Nginx configuration. Also, check for any buffering settings (`proxy_buffering`) that might be interfering with the response.