CERT_UNTRUSTED Error Response from Amazon SNS from Node.js

I am using sns-mobile to register mobile device with Amazon SNS. I followed this tutorial on SNS Push Notifications using nodejs.

The code for creating the SNS object looks like the following:

var myApp = new SNS({
    platform: SNS.SUPPORTED_PLATFORMS.ANDROID,
    region: 'eu-west-1',
    apiVersion: '2010-03-31',
    accessKeyId: config.sns.key_id,
    secretAccessKey: config.sns.secret_key_id,
    platformApplicationArn: config.sns.arn
});

The code for registering/adding the user or device in this case is the following:

// Add the user to SNS
myApp.addUser(deviceId, null, function(err, endpointArn) {
    // SNS returned an error
    if(err) {
        console.log(err);
        return res.status(500).json({
            status: 'error occurred registering device'
        });
    }

    // Tell the user everything is ok
    res.status(200).json({
        status: 'ok'
    });
});

The error logged to the console is the following:

{ [Error: CERT_UNTRUSTED]
  message: 'CERT_UNTRUSTED',
  code: 'NetworkingError',
  region: 'eu-west-1',
  hostname: 'sns.eu-west-1.amazonaws.com',
  retryable: true,
  time: Sun Mar 08 2015 17:13:44 GMT-0700 (US Mountain Standard Time),
  statusCode: undefined }

I tried looking around for reasons why this may be happening, but keep coming across claims that it is a problem with nodejs.

Any ideas how to get around this?