ElasticSearch failed to parse date field

I have the following query that I'm trying to run on Elasticsearch 5.6 in Kibana Dev Tools:

{
  "query": {
    "bool": {
      "filter": {
        "bool": {
          "must": [
            {
              "range": {
                "inserted": {
                  "gt": "Thu Aug 20 09:01:31 +0100 2020"
                }
              }
            }
          ]
        }
      }
    }
  }
}

the response I'm getting is:

{
  "error": {
    "root_cause": [
      {
        "type": "parse_exception",
        "reason": "failed to parse date field [Thu Aug 20 09:01:31 +0100 2020] with format [EEE MMM dd HH:mm:ss ZZZ yyyy]"
      }
    ],
    "type": "search_phase_execution_exception",
    "reason": "all shards failed",
    "phase": "can_match",
    "grouped": true,

The datetime format looks correct to me, what am I doing wrong?

In Short: 'EEE MMM dd HH:mm:ss Z yyyy' is the correct format.

Details:

1. Elastic Search uses Joda library for formatting DateTime.

Excerpt from ES Docs
> Completely customizable date formats are supported. The syntax for these is explained in the Joda docs.

2. Try formatting DateTime with the pattern you are using "EEE MMM dd HH:mm:ss ZZZ yyyy" using Joda library. Programming language is Java

> DateTimeFormatter formatter = DateTimeFormat.forPattern("EEE MMM dd HH:mm:ss ZZZ yyyy");
> DateTime dateTime = formatter.parseDateTime("Thu Aug 20 09:01:31 +0100 2020");

It is resulting in below exception :

> Exception in thread "main" java.lang.IllegalArgumentException: Invalid
> format: "Thu Aug 20 09:01:31 +0100 2020" is malformed at "+0100 2020"
> at
> org.joda.time.format.DateTimeFormatter.parseDateTime(DateTimeFormatter.java:866)

Deduction: There is something wrong with the format defined by 'ZZZ'

From JodaDoc
> Z time zone offset/id zone -0800

3. Based on the investigation correct format is "EEE MMM dd HH:mm:ss Z yyyy" and not "EEE MMM dd HH:mm:ss ZZZ yyyy".

4. Considering #3 define format in your mapping like

> {
> "mappings": {
> "_doc":{
> "properties": {
> "inserted":{
> "type": "date",
> "format": "EEE MMM dd HH:mm:ss Z yyyy"
> }
> }
> }
> }
> }