Cannot GET /index after following video exactly

Despite following the directions exactly, plus rewatching, and stopping to check, I get the Cannot GET /index error. Any ideas why? Below is my app.js code: 'use strict';

var express = require('express'), posts = require('./mock/posts.json');

var app = express();

app.set('view engine', 'jade'); app.set('views', __dirname + '/templates')

app.get('/', function(req, res){ res.render('index') });

app.get('/blog/:title?', function(req, res){ var title = req.params.title; if (title === undefined) { res.status(503); res.send("This page is under construction!"); } else { var post = posts[title]; res.send(post); } });

app.listen(3000, function() { console.log("The frontend server is running on port 3000!"); });

This is my index.jade code: doctype html html(lang="en") head title Landing Page body h1 "The future home of something awesome!" p Jujubes wafer jelly-o chocolate bar I love lemon drops tootsie roll marzipan. Tart biscuit biscuit apple pie bear claw I love powder brownie. Icing I love macaroon toffee I love chupa chups donut donut. Cake dragée bonbon macaroon sweet candy canes gummies sugar plum chocolate. Macaroon candy muffin.