Connecting Mongoose to MLab H10 503

Question

I'm getting an H10 error with my node app on Heroku. It was working fine until I added Google analytics to my EJS files. My env port is set fine, the only other thing I think it could be is my connection to my MongoDB database on MLab...

Here's the app file:

var express = require('express'),
app = express(),
router = express.Router(),
ejs = require('ejs'),
bodyParser = require('body-parser'),
passport = require('passport'),
LocalStrategy = require('passport-local'),
mongoose = require('mongoose'),
flash = require('connect-flash'),
methodOverride = require('method-override'),
Post = require('./models/post'),
helmet = require('helmet'),
Comment = require("./models/comment"),
Email = require("./ignore/email"),
Raph = require("./ignore/raphuser"),
User = require('./models/user'),
nodemailer = require('nodemailer');
postRoutes = require('./routes/posts');


app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));
app.use(methodOverride("_method"));
app.set('view engine', 'ejs');

app.use(passport.initialize());
app.use(passport.session());
passport.use(new LocalStrategy(User.authenticate()));
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());


app.use('/api/posts', postRoutes);
app.use(helmet());
app.use(flash());

app.use(express.static(__dirname + '/views'));
app.use(express.static(__dirname + '/public'));

// then my routes

app.listen(process.env.PORT || 5000);

And also my connection to MLab:

var mongoose = require('mongoose');
mongoose.set('debug', true);
mongoose.connect("mongodb://myusername:mypassword@ds147390.mlab.com:47390/dbname");

mongoose.Promise = Promise;

module.exports.Post = require('./post');