Struggling with date ranges

[brandondash (Brandon Biondo)]

I am trying to use a date range for a query using a field other than @timestamp. I can't figure out what I'm doing wrong.

Here is the original query that works and uses @timestamp:

{
"size": 500,
"query": {
    "bool": {
        "must": [
            {
                "query_string": {
                    "query": "+\"MeetingStartedEvent\"",
                    "analyze_wildcard": true
                }
            },
            {
                "range": {
                    "@timestamp": {
                        "gte": 1533224298156,
                        "lte": 1533231149003,
                        "format": "epoch_millis"
                    }
                }
            }
        ],
        "must_not": []
    }
},
"_source": [ "meetingId", "event_time" ]
}

It returns plenty of results, one of which looks like this:

{
  "_index" : "logstash-2018.08.02",
  "_type" : "foo",
  "_id" : "AWT7qhivumgVPlrZNYdf",
  "_score" : 16.294584,
  "_source" : {
    "meetingId" : "1487972933889",
    "event_time" : "2017-02-24 21:49:07"
  }
}

The problem is that I don't want to filter based on when the log makes it into ES. I want to filter based on when the event happened (in this case, event_time). So I used this documentation and changed my range filter to look like this:

"range": {
    "event_time": {
        "format": "yyyy-MM-dd HH:mm:ss",
        "gte": "2017-02-24 00:00:00",
        "lte": "2017-02-24 11:59:59"
    }
}

I expected I would get the same result as the one listed above (plus a handful of others); instead, I get this:

{
    "took" : 75,
    "timed_out" : false,
    "_shards" : {
        "total" : 5,
        "successful" : 5,
        "failed" : 0
    },
    "hits" : {
        "total" : 0,
        "max_score" : null,
        "hits" : [ ]
    }
}

Any idea what I'm missing?