Heroku h12 and 503 errors are occured - node.js

Question

enter image description hereI want to deploy the node.js server to heroku. But when I'm trying to get JSON file from server, h12, 503 errors were occured...
This is my git address. Branch is CHOI-HYO-GIL.
https://github.com/js-yu1592/capstone-design.git
This is package.json
{
enter image description here
"name": "lastproject",
"version": "1.0.0",
"description": "",
"main": "index1.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "nodemon index1.js"
},
"engines": {
"npm": "6.13.6",
"node": "13.5.0"
}
,
"author": "",
"license": "ISC",
"dependencies": {
"bcrypt": "^3.0.7",
"bcrypt-nodejs": "0.0.3",
"cookie-parser": "^1.4.4",
"dotenv": "^8.2.0",
"ejs": "^3.0.1",
"express": "^4.17.1",
"express-session": "^1.17.0",
"firebase": "^7.8.0",
"firebase-admin": "^8.9.2",
"firebaseui": "^4.4.0",
"morgan": "^1.9.1",
"mysql2": "^2.1.0",
"passport": "^0.4.1",
"passport-local": "^1.0.0",
"pug": "^2.0.4",
"sequelize": "^5.21.3",
"sequelize-cli": "^5.5.1",
"serve-favicon": "^2.5.0",
"session-file-store": "^1.4.0",
"socket.io": "^2.3.0"
},
"devDependencies": {
"connect-flash": "^0.1.1",
"nodemon": "^2.0.2"
}
}
This is index1.js
const express = require('express')
const port =process.env.PORT||3000;
const app=express()
const bodyParser = require('body-parser');
require('dotenv').config();
const { sequelize } = require('./models');
var admin = require("firebase-admin");
var serviceAccount = require("./graduation-f5a8d-firebase-adminsdk-3a1to-44789ec1c4.json");
admin.initializeApp({
credential: admin.credential.cert(serviceAccount),
databaseURL: "https://graduation-f5a8d.firebaseio.com"
});
var user_info=require('./routes/user_info')
var user_fish=require('./routes/user_fish')
var home=require('./routes/home')
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json())
app.use(express.static('public'));
app.use('/user_fish',user_fish);
app.use('/user_info',user_info);
app.use('/',home)
app.listen(port, ()=>console.log('Example app listening on port ${port}!'))