I do have planned property in my gantt chart, but still not working

{
          "hidden": false,
          "baselineFn": "0001-01-01T00:00:00",
          "baselineSt": "0001-01-01T00:00:00",
          "resources": [],
          "tasks": null,
          "connections": [
            {
              "target": 3,
              "type": 1
            }
          ],
          "planned": [
            {
              "dateStart": "2023-09-19",
              "dateEnd": "2023-09-23"
            }
          ]
        }