ELK Stack on Ubuntu 16.04 with Magento Servers as Filebeat clients

Hi all, I have 2 droplets configured in my DO project:

1. ELK Stack
2. Magento eCommerce platform on a LAMP Stack

Both instances are up and running, with all services setup. However, I am having an issue with my Magento server, which is configured as the Filebeat client, sending its system logs over to the ELK stack.

I’ve followed the instructions from this KB article: https://www.digitalocean.com/community/tutorials/how-to-install-elasticsearch-logstash-and-kibana-elk-stack-on-ubuntu-14-04

I’m stuck at the “Test Filebeat Installation” section and no matter what I’m trying with the Filebeat configuration the logs do not seem to be getting sent to the ELK stack. I’ve gone back through the configurations a few time to ensure I have it setup properly, but it’s possible I’m overlooking something simple.

When I search for filebeat logs on the ELK stack I get 0 hits (see below extract from my terminal). Can anyone provide any guidance/suggestions on where to troubleshoot?

curl -XGET 'http://localhost:9200/filebeat-*/_search?pretty'
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 0,
    "successful" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 0,
    "max_score" : 0.0,
    "hits" : [ ]
  }
}

Thanks in advance!