 <p>Just try changing <code>port</code> in </p> <pre><code>connect: { options: { port: 9000, // Change this to '0.0.0.0' to access the server from outside. hostname: 'localhost', livereload: 35729 }, </code></pre> <p>I used port 8999 instead of 9000 and it simply worked.</p> <p><strong>Edit</strong>: I forgot to mention that I was receiving the very same error as you when running <code>grunt server</code>. I'm on Windows 7.</p>