How can I fix `err_ssl_protocol_error` in a Node.js application running on localhost?

For Node.js, ensure your server isn't enforcing HTTPS unnecessarily. If you're using HTTPS, verify your certificate is correctly configured and trusted by your system. A common fix is to disable HTTPS entirely for local development by removing or commenting out the HTTPS-related code in your server setup. Alternatively, use a self-signed certificate and configure your browser to trust it (though this is less secure and not recommended for production).