Ajax on codeigniter 4

Hey guys, how are you?

I´m trying to use ajax on my ci4 application, but is not working. I want the select boxes changing according the countries and states selected. Please, some help?

.js
________

$( ".pais" ).change(function() {

    var id_pais= $("#pais").val();

    var base_url= "<?php echo base_url();?>";

    $.post(base_url+'/index.php/estado/getEstado', {
        id_pais : id_pais
    },function (data) {
        $("#estado").html(data);
        $("#estado").removeAttr('disabled');
    });
});
________

Model
________

namespace App\Models;

use CodeIgniter\Model;

class EstadoModel extends Model
{
    //Atributos de configuração

    protected $table='estado';
    protected $primaryKey= 'id';

    //Metodo GET
    public function getEstado($id_pais){

        return $this->asArray()->where(['pais' => $id_pais])->first();

    }

}
________

Controller
________

use App\Models\EstadoModel;

class Estado extends BaseController
{
    public function getEstado()
    {
        $id_pais= $this->request->getVar('id_pais');

        $model = new EstadoModel();

        echo $model->getEstado($id_pais);
    }
}
________

Note: Error code 403 to ajax response (I see this in the inspect element on my browser - Network).