Heroku crash over and over by POST request, multer

问题:

My deployment on Heroku keep crashing on the POST request when I send the mulitpart form. I can't see in the logs if it's on the upload (multer) function, save (mongoose) function or sendMail (nodemailer) function. The only thing I see in the logs is a H18 error: Internal Server.

Router.js

const express = require("express");
const mongoose = require("mongoose");
const router = express.Router();
const multer = require("multer");
const path = require("path");
const File = require("../models/Files");
const mail = require("../handlers/mailer");

// Set storage engine
const storage = multer.memoryStorage();

// Init upload
const upload = multer({
  storage: storage
}).single("file");

router.get("/", (req, res) => {
  res.render("index");
});

router.post("/send", async (req, res, next) => {

  await upload(req, res, async err => {
    if (err) {
      console.log("error by uploading file:", err);
    } else {
      console.log(`File is uploaded to the memoryStorage: ${req.file.originalname} `);
    }

    // Create a model to save in the database
    const fileUpload = new File({
      fromEmail: "<[e-mail]>",
      fromName: '"Dennis Klarenbeek