数据表 AJAX POST 被弹性拒绝：预期 [START_OBJECT] 但找到 [VALUE_STRING]

问：

我正在尝试修复与 mu 本地弹性实例的连接，但在尝试使用服务器端调用时仍然出现各种错误。

经过各种尝试，我遇到了“预期 [START_OBJECT] 但发现 [VALUE_STRING]”的情况。

试图通过互联网找到原因和解决方案，但没有成功。

这是我的代码。

<script>
$(document).ready(function () {
    var query = '{ "query" : { "match_all" : {} } }';
    console.log (query);
    query = JSON.stringify(query);
    console.log (query);
        
    $('#integrations').DataTable( {
            "processing": true,
            "serverSide": true,
      "ajax": {
                "url": "http://localhost:9200/integrations-prod/_search?size=1000&source_content_type=application/json",
                //WORKS EVEN WITH GET BUT NOT AS SERVERSIDE "url": `http://czchown5029751.prg-dc.dhl.com:9200/integrations-prod/_search?size=1000&source_content_type=application/json&source=${query}`,
                //WORKS EVEN WITH GET BUT NOT AS SERVERSIDE "url": `http://czchown5029751.prg-dc.dhl.com:9200/integrations-prod/_search?size=10000`,
                data : function ( d ) {
                return query;
            },
                "contentType": "application/json",
                //"cache": "false",
        "type": "POST",
        //"jsonp": "true",
        "dataType": "json",
        "dataSrc": "hits.hits",
            "columnDefs": [ { "defaultContent": "-", "targets": "_all" } ]
            },
            "columns": [
            { "data": "_source.name" },
            { "data": "_source.description" },
            { "data": "_source.valid" },
            { "data": "_source.status_id" },
            { "data": "_source.region_id" },
            { "data": "_source.validated_time" }
        ]
    } )
}); 
</script>