botkit: Not connecting to slack RTM

When I run the bot It gets stuck on this message:

token=my-real-slack-token node bot.js
** No persistent storage method specified! Data may be lost when process shuts down.
** Setting up custom handlers for processing Slack messages
** API CALL: https://slack.com/api/rtm.start
** BOT ID:  catbot  ...attempting to connect to RTM!

Here’s the code:

var Botkit = require('botkit')

if (!process.env.token) {
  console.log('Error: Specify token in environment')
  process.exit(1)
}

var controller = Botkit.slackbot({
 debug: false,
})

controller.spawn({
  token: process.env.token
}).startRTM(function(err) {
  if (err) {
    throw new Error(err)
  }
})

function rand(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

var listeners = 'direct_message, direct_mention, mention'
controller.hears(['rand'], listeners, function(bot, message) {
    bot.reply(message, rand(1,100))
})