POST路由可在localhost上运行，但不能在服务器上运行

Question

使我的Web应用程序在digitalocean服务器上工作时遇到问题。一切都可以在localhost上正常运行，但是一旦在服务器上我就无法发布/ kontakt

这是我的ejs模板表格

<form action="/kontakt" method="post">
                            <input type="text" minlength="4" placeholder="MENO" name='email[name]' required>
                            <input type="email" placeholder="E-MAIL" name='email[email]' required>
                            <textarea id="" minlength="20" cols="30" rows="4" placeholder="SPRÁVA" name='email[text]' required></textarea>
                            <button>ODOSLAŤ</button>
                        </form>

和我的app.js

if(process.env.NODE_ENV !== 'production'){
    require('dotenv').config()
}

const express = require('express'),
    indexapp = require('./routes/index'),
    nodemailer = require('nodemailer'),
    flash = require('connect-flash'),
    bodyParser = require('body-parser'),
    cookieParser = require('cookie-parser'),
    session = require('express-session'),
    app = express(),
    mailapp = require('./routes/mail');


app.set('view engine' , 'ejs')
app.set('views', __dirname + '/views')
app.use(express.static('public'))

app.use(cookieParser('secret'));
app.use(session({cookie: { maxAge: 60000 }}));
app.use(flash());


app.use(express.urlencoded()); 
    let transporter = nodemailer.createTransport({
    service: 'Gmail',
    auth: {
        user: '*****',
        pass: '*****',
    },
});

app.post('/kontakt', (req,res) => {

  transporter.sendMail({
      'transporter settings'
  res.redirect('/kontakt')
})

app.use('/', indexapp)

app.listen(process.env.PORT || 3000) 

有人知道怎么了吗？