Heroku is giving me a 503 and I don't know why - node.js

Question

So Heroku displays my front end fine, but when I make a call to my back end it only returns a 503 and I've had no luck with google finding an answer to my problem.
Here's my server
const restify = require('restify');
const mongoose = require('mongoose')
const db = mongoose.connection
const router = require('./routes')
let PORT = process.env.PORT || process.env.VUE_APP_HOST
require('dotenv').config()
const server = restify.createServer({
name: 'myapp',
version: '1.0.0'
})
server.use(restify.plugins.acceptParser(server.acceptable))
server.use(restify.plugins.queryParser());
server.use(restify.plugins.bodyParser());
router.applyRoutes(server)
const uri = process.env.SERVER
mongoose.connect(uri, {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex:true
},
() => console.log('Database connected'))
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function () {
// we're connected!
console.log('mongoose is connected')
})
server.get('/*', restify.plugins.serveStatic({
directory: './dist',
default: 'index.html',
}));
server.listen(PORT, function () {
console.log('%s listening at %s', server.name, server.url);
});
Here is my log file
-----> Node.js app detected
-----> Creating runtime environment
NPM_CONFIG_LOGLEVEL=error
NODE_ENV=production
NODE_MODULES_CACHE=true
NODE_VERBOSE=false
-----> Installing binaries
engines.node (package.json): 13.8.0
engines.npm (package.json): unspecified (use default)
Resolving node version 13.8.0...
Downloading and installing node 13.8.0...
Using default npm version: 6.13.6
-----> Restoring cache
- node_modules
-----> Installing dependencies
Installing node modules (package.json + package-lock)
audited 19449 packages in 12.185s
46 packages are looking for funding
run `npm fund` for details
found 13 vulnerabilities (11 low, 2 moderate)
run `npm audit fix` to fix them, or `npm audit` for details
-----> Build
Running build
> quiz#0.1.0 build /tmp/build_1b1e8d06246614eaf4f8c73b7396ab26
> vue-cli-service build
- Building for production...
WARNING Compiled with 2 warnings9:31:34 PM
warning
asset size limit: The following asset(s) exceed the recommended size limit (244 KiB).
This can impact web performance.
Assets:
css/chunk-vendors.f2de1e82.css (291 KiB)
js/chunk-vendors.25e54ca6.js (249 KiB)
warning
entrypoint size limit: The following entrypoint(s) combined asset size exceeds the recommended limit (244 KiB). This can impact web performance.
Entrypoints:
app (550 KiB)
css/chunk-vendors.f2de1e82.css
js/chunk-vendors.25e54ca6.js
css/app.83b7036f.css
js/app.d2d7e1c2.js
File Size Gzipped
dist/js/chunk-vendors.25e54ca6.js 249.22 KiB 83.71 KiB
dist/js/chunk-322ddd76.30a6d833.js 84.76 KiB 22.35 KiB
dist/js/chunk-7a6727f2.c0631d11.js 21.09 KiB 6.60 KiB
dist/js/chunk-fd105068.4e2b7450.js 20.63 KiB 5.84 KiB
dist/js/chunk-5e9478d9.aa473c10.js 11.85 KiB 3.72 KiB
dist/js/app.d2d7e1c2.js 9.00 KiB 3.59 KiB
dist/js/chunk-ef9ba634.75ba4138.js 4.23 KiB 1.78 KiB
dist/js/chunk-20b8df38.167c1cfd.js 2.49 KiB 1.09 KiB
dist/js/chunk-2d0ac3bd.a6df4124.js 2.18 KiB 1.05 KiB
dist/js/chunk-2d20ec06.bc0797f6.js 1.77 KiB 0.92 KiB
dist/js/chunk-beee9c80.2f37298d.js 1.37 KiB 0.64 KiB
dist/js/chunk-2d230542.1693dee0.js 1.23 KiB 0.73 KiB
dist/css/chunk-vendors.f2de1e82.css 291.44 KiB 32.34 KiB
dist/css/chunk-fd105068.ee4c284f.css 35.29 KiB 4.49 KiB
dist/css/chunk-322ddd76.fa9ee5dc.css 24.36 KiB 3.88 KiB
dist/css/chunk-beee9c80.0670aa22.css 9.98 KiB 1.31 KiB
dist/css/chunk-5e9478d9.6c52e948.css 8.44 KiB 1.71 KiB
dist/css/chunk-7a6727f2.e044490b.css 3.71 KiB 1.00 KiB
dist/css/chunk-20b8df38.c7315fda.css 0.89 KiB 0.35 KiB
dist/css/app.83b7036f.css 0.03 KiB 0.05 KiB
Images and other types of assets omitted.
DONE Build complete. The dist directory is ready to be deployed.
INFO Check out deployment instructions at https://cli.vuejs.org/guide/deployment.html
-----> Caching build
- node_modules
-----> Pruning devDependencies
removed 1037 packages and audited 444 packages in 13.024s
13 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities
-----> Build succeeded!
-----> Discovering process types
Default types for buildpack -> web
-----> Compressing...
Done: 50.5M
-----> Launching...
Released v46
https://quizzor.herokuapp.com/ deployed to Heroku
I cannot find any info on how to resolve this. When I run my server locally everything is fine, but Heroku just seems to hate me.

Answer 1

I went to my mongodb atlas page and whitelisted every IP address. I then set my DB connection string to a variable within Heroku.