问Heroku || Error R10 (启动超时) -> Web进程无法在启动后60秒内绑定到$PORT

EN

2020-09-29T04:24:09.365962+00:00 app[web.1]: production
2020-09-29T04:24:09.415266+00:00 app[web.1]: server is listening at port 40890
2020-09-29T04:24:09.942808+00:00 app[web.1]: DB connection succesfull
2020-09-29T04:25:03.400919+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2020-09-29T04:25:03.433351+00:00 heroku[web.1]: Stopping process with SIGKILL
2020-09-29T04:25:03.559247+00:00 heroku[web.1]: Process exited with status 137
2020-09-29T04:25:03.607404+00:00 heroku[web.1]: State changed from starting to crashed

const dotenv = require('dotenv');
const mongoose = require('mongoose');
dotenv.config({ path: './config.env' });
const app = require('./app');


require('dotenv').config();

const DB = process.env.DATABASE.replace(
  '<PASSWORD>',
  process.env.DATABASE_PASSWORD
);

mongoose
  .connect(DB, {
    useUnifiedTopology: true,
    useNewUrlParser: true,
    useCreateIndex: true,
    useFindAndModify: false
  })
  .then(con => {
    console.log('DB connection succesfull');
  });


const PORT = process.env.PORT | 3000;

const server = app.listen(PORT, () => {
  console.log(`server is listening at port ${PORT}`);
});