Node.js Express:OpenSSL错误：_tls_common.js:129 c.context.setCert（cert）；

我正在尝试将HTTPS与OpenSSL和HTTPS核心模块一起使用，下面是我的代码：

App.js：

const url = config.mongoUrl;
const connect = mongoose.connect(url, { useNewUrlParser: true, useUnifiedTopology: true });

connect.then(db => {
console.log("Connected correctly to server!");
}, err => console.log(err))

var app = express();

app.all('*', (req, res, next) => {
  if (req.secure) {
    return next();
  }
  else {
    res.redirect(307, 'https://' + req.hostname + ':' + app.get('secPort') + req.url);
  }

/bin/www:

var port = normalizePort(process.env.PORT || '3000');
app.set('port', port);
app.set('secPort', port + 443);

/**
 * Create HTTP server.
 */
 
var options = {
  key: fs.readFileSync(__dirname+'/private.key'),
  cert: fs.readFileSync(__dirname+'/certificate.pem')
};

var secureServer = https.createServer(options, app);


/**
 * Listen on provided port, on all network interfaces.
 */

secureServer.listen(app.get('secPort'), () => {
   console.log('Server listening on port ',app.get('secPort'));
});
secureServer.on('error', onError);
secureServer.on('listening', onListening);
});

我在./bin中使用以下命令创建了certificate.pem、private.key和cert.csr：

openssl genrsa 1024 > private.key
openssl req -new -key private.key -out cert.csr
openssl x509 -req -in cert.csr -signkey private.key -out certificate.pem

但当我执行npm start时，nodemon给了我一个错误：

_tls_common.js:129
      c.context.setCert(cert);

我做错什么了吗