I am trying to integrate the .php files that Datatables offers for the serverside option.

but I can't know because it doesn't show me data.

this is my js table

table16=$('#enfriamiento').DataTable({
    dom: 'Blftipr',
    'processing': true,
    'serverSide': true,
    search: {search: respuesta},
    "ajax": {
        "url": "serverside/show.enfriamiento.php",
        "type": "POST" ,
    },
    "order": [0, 'asc'],
    "columns": [
        { data: 1 },
        { data: 2 },
        { data: 3 },
        { data: 4 },
        {

            "render": function ( data, type, row ) {

                let dt1 = moment(row[5], ["HH:mm"]).format("hh:mm A");

                return dt1;

            }
        },
        {

            "render": function ( data, type, row ) {

                let dt1 = moment(row[6], ["HH:mm"]).format("hh:mm A");

                return dt1;

            }
        },
        { data: 7 },
        { data: 8 },
        { data: 9 },
        { data: 10 },
        { data: 11 },
        { data: 12 },
        { data: 13 },
        { data: 14 },
        { data: 15 },
        { data: 16 },
        { data: 17 },
        { data: 18 },
        { data: 19 },
        { data: 20 },
        { data: 21 },
        { data: 22 },
        { data: 23 },
        { data: 24 },
        { data: 25 },
        { data: 26 },
        { data: 27 },
        { data: 28 },
        { data: 29 },
        { data: 30 },
        { data: 31 },
        { data: 32 },
        { data: 33 },
        { data: 34 },
        { data: 35 },
        { data: 36 },
        { data: 37 },
        { data: 38 },
        {

            "render": function ( data, type, row ) {

                let dt1=null;

                if (row[39]!=null || row[39]!='') {
                    dt1 = moment(row[39], ["HH:mm"]).format("hh:mm A");
                }

                return dt1;

            }
        },
        {

            "render": function ( data, type, row ) {

                let dt2=null;

                if (row[40]!=null && row[40]!='') {
                    dt2 = moment(row[40], ["HH:mm"]).format("hh:mm A");
                }

                return dt2;

            }
        },
        { data: null,
            orderable: false,
            "visible": TIPO_USER === 'ADMINISTRADOR' || USUARIO_LOGUEO==="ADRIANC" || USUARIO_LOGUEO==="STEFAB" || USUARIO_LOGUEO==="DANIP" || USUARIO_LOGUEO==="ABADIA" ? true : false,
            "render": function ( data, type, row ) {

                if (!row[40]) {
                    return false;
                }else{
                    return row[40];
                }

            }
        }
    ],
    "lengthMenu": [[15, 25, 50], [15, 25, 50]],
    /*activo la el scroll dentro de la tabla para poder depararme y obtener vista de todas las columnas-filas */
    "scrollY": 300,
    "scrollX": true,
    "columnDefs": [
        { className: "dt-body-left", "targets": [ 0 ] }
    ],
    /*aquí estoy filtrando las columnas de donde obtendré los datos cuando se escribe algo en el buscador*/
    columnDefs: [
        { targets: [3, 5], searchable: true},
        { targets: '_all', searchable: false }
    ],
    "rowCallback":function(row, data){
        //console.log("hora ini: ",data[39]);

        if(data[39] == "" || data[39] == null){

            $('td:eq(38)', row).css("background-color","#DAA520");
            $('td:eq(38)', row).html("<strong>FALTA HORA INICIO</strong>");
        }
        //console.log("hora FIN: ",data[40]);
        if(data[40] == "" || data[40] == null){

            $('td:eq(39)', row).css("background-color","#DAA520");
            $('td:eq(39)', row).html("<strong>FALTA HORA FINAL</strong>");

        }

    },
    "initComplete": function(){

        //para evitar que el servidor y el renderizado colapse, haciendo llamadas ajax
        $("#enfriamiento_filter input").unbind().bind("input", function(e) { // Bind our desired behavior

            if(this.value.length == 6) {

                // Call the API search function
                table16.search(this.value).draw();
            }

        });

    }
});

this is my file serverside/show.enfriamiento.php. coded with a Datatable example

    <?php
    /*
     * DataTables example server-side processing script.
     *
     * Please note that this script is intentionally extremely simple to show how
     * server-side processing can be implemented, and probably shouldn't be used as
     * the basis for a large complex system. It is suitable for simple use cases as
     * for learning.
     *
     * See http://datatables.net/usage/server-side for full details on the server-
     * side processing requirements of DataTables.
     *
     * @license MIT - http://datatables.net/license_mit
     */

    /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     * Easy set variables
     */

    // DB table to use
    $table = 'view_control_etapa_enfri';

    // Table's primary key
    $primaryKey = 'cod_piku';

    // Array of database columns which should be read and sent back to DataTables.
    // The `db` parameter represents the column name in the database, while the `dt`
    // parameter represents the DataTables column identifier. In this case object
    // parameter names
    $columns = array(
        array( 'db' => 'cod_piku', 'dt' =>  0 ),
        array( 'db' => 'fecha_registro', 'dt' =>    1 ),
        array( 'db' => 'persona_resp', 'dt' =>  2 ),
        array( 'db' => 'lote_piku', 'dt' => 3 ),
        array( 'db' => 'viaje', 'dt' => 4 ),
        array( 'db' => 'hora_entrada', 'dt' =>  5 ),
        array( 'db' => 'hora_salida', 'dt' =>   6 ),
        array( 'db' => 'tiempo_total', 'dt' =>  7 ),
        array( 'db' => 'chiller1_cloro_agua', 'dt' =>   8,
            'formatter' => function($d, $row)
            {
                return floatval($d);
            }
        ),
        array( 'db' => 'chiller1_acido_peracetico', 'dt' => 9 ),
        array( 'db' => 'chiller2_cloro_agua', 'dt' => 10 ),
        array( 'db' => 'chiller2_acido_peracetico', 'dt' => 11 ),
        array( 'db' => 'chiller3_temp_agua', 'dt' => 12 ),
        array( 'db' => 'chiller3_cloro_residual', 'dt' => 13 ),
        array( 'db' => 'chiller3_acido_peracetico', 'dt' => 14 ),
        array( 'db' => 'chiller3_temp_canal', 'dt' => 15 ),
        array( 'db' => 'chiller4_temp_agua', 'dt' => 16 ),
        array( 'db' => 'chiller4_temp_canal', 'dt' => 17 ),
        array( 'db' => 'chiller4_cloro_residual_agua', 'dt' => 18 ),
        array( 'db' => 'chiller4_acido_peracetico', 'dt' => 19 ),
        array( 'db' => 'despre_temp_pollo', 'dt' => 20 ),
        array( 'db' => 'despre_temp_pollo_marinado', 'dt' => 21 ),
        array( 'db' => 'despre_temp_c_pollo_entra_cuart', 'dt' => 22 ),
        array( 'db' => 'correcion_term_codigo', 'dt' => 23 ),
        array( 'db' => 'correcion_term_correcion', 'dt' => 24 ),
        array( 'db' => 'salmuera_lote_salmuera', 'dt' => 25 ),
        array( 'db' => 'salmuera_fecha_produccion', 'dt' => 26 ),
        array( 'db' => 'salmuera_fecha_vencimiento', 'dt' => 27 ),
        array( 'db' => 'salmuera_proveedor', 'dt' => 28 ),
        array( 'db' => 'salmuera_temp_c_preparacion', 'dt' => 29 ),
        array( 'db' => 'salmuera_temp_c_marinadora', 'dt' => 30 ),
        array( 'db' => 'salmuera_temp_c_recirculada', 'dt' => 31 ),
        array( 'db' => 'higados_c', 'dt' => 32 ),
        array( 'db' => 'molleja_c', 'dt' => 33 ),
        array( 'db' => 'pata_c', 'dt' => 34 ),
        array( 'db' => 'pescuezo_c', 'dt' => 35 ),
        array( 'db' => 'corazones_c', 'dt' => 36 ),
        array( 'db' => 'temp_pro_viscera_c', 'dt' => 37 ),
        array( 'db' => 'observacion', 'dt' => 38 ),
        array( 'db' => 'hora_ini_viaje', 'dt' => 39 ),
        array( 'db' => 'hora_fin_viaje', 'dt' => 40 )

    );

    // SQL server connection information
    $sql_details = array(
        'user' => 'root',
        'pass' => 'root',
        'db'   => 'bd',
        'host' => 'localhost'
    );


    /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
     * If you just want to use the basic configuration for DataTables with PHP
     * server-side, there is no need to edit below this line.
     */
    /* ( '/ ssp.class.php' ) */
    require_once '../serverside/ssp.class.php';

    echo json_encode(
        SSP::simple( $_POST, $sql_details, $table, $primaryKey, $columns )
    );

this is the answer i always get

{"draw":14,"recordsTotal":1588,"recordsFiltered":0,"data":[]}