Signalmaster on https: ERR_CONNECTION_REFUSED

I have an ember project using Signalmaster. In the config/environment.js I have the following:

if (environment === 'production') {

ENV.SIGNALMASTER = {
  HOST: 'https://localhost:8890',
  PORT: '8890',
  FORCE_CONNECTION: true
};

On my server I have signalmaster running at https://localhost:8890 (in the development.json and production.json files in the config directory for signalmaster I have secure set to true, and in the server.js file for signalmaster I've put in the location of my SSL certificate and key, as is required for running it on https) - when running "node server.js" I get the following:

signal master is running at: https://localhost:8890

Running "netstat -lnp" also shows a process running on port 8890. However when I use the app I get errors like this:

GET https://localhost:8890/socket.io/?EIO=3&transport=polling&t=LjG8--J net::ERR_CONNECTION_REFUSED

I am using socket.io version 1.3.7.