Unable to create an Index and send logs to Elasticsearch from Logstash getting 404 error

Elastic Stack Logstash
1

We are not able to create an Index on Elasticsearch using logstash. when I try the access indices I see 404 on the Elasticsearch

<{
  "error" : {
    "root_cause" : [
      {
        "type" : "index_not_found_exception",
        "reason" : "no such index [security_audit-log-ap]",
        "resource.type" : "index_or_alias",
        "resource.id" : "security_audit-log-ap",
        "index_uuid" : "_na_",
        "index" : "security_audit-log-ap"
      }
    ],
    "type" : "index_not_found_exception",
    "reason" : "no such index [security_audit-log-ap]",
    "resource.type" : "index_or_alias",
    "resource.id" : "security_audit-log-ap",
    "index_uuid" : "_na_",
    "index" : "security_audit-log-ap"
  },
  "status" : 404
}>
2

below is the [this is the github link for our logstach configuration](https://github.com/bitsofinfo/logstash-modsecurity)