Elastic exits with network.host set

I have installed Elastic on the latest ubuntu server. I cannot connect to Elastic from other hosts. I can connect to the server using SSH and I can see in netstat that 9200 is bound to 127.0.0.1.

I can curl to Elastic from the server itself, shown below.

root@elk:/etc/elasticsearch# curl -X GET "localhost:9200/?pretty"
{
  "name" : "elk",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "Tsvs-ltLSLWZ8tYpYoI4eg",
  "version" : {
    "number" : "7.3.0",
    "build_flavor" : "default",
    "build_type" : "deb",
    "build_hash" : "de777fa",
    "build_date" : "2019-07-24T18:30:11.767338Z",
    "build_snapshot" : false,
    "lucene_version" : "8.1.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },

}

If I set the network.host to anything at all, elastic exits with:

Aug 13 22:30:07 elk systemd[1]: elasticsearch.service: Main process exited, code=exited, status=78/n/a
Aug 13 22:30:07 elk systemd[1]: elasticsearch.service: Failed with result 'exit-code'.

What causes this?

Any assistance would be greatly appreciated.

Welcome!

Read elasticsearch logs. They are pretty much explicit.

And then read https://www.elastic.co/guide/en/elasticsearch/reference/current/bootstrap-checks.html

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