Unexpected error while getting the method or property insert on object Apiary.dfareporting.ads

Question

I try to call this API with the following ad object.

  var ad = DoubleClickCampaigns.Ads.insert(
    {
      
      "campaignId": parseInt(singlePlacementArray[0]),
      "advertiserId": parseInt(inputSheet.getRange("J9").getValue()),
      
      //"accountId": inputSheet.getRange("H9").getValue(),
      "name": singlePlacementArray[1],
       "active": true,
       "archived": false,
      "type": "AD_SERVING_TRACKING",
      "startDate": Utilities.formatDate(singlePlacementArray[5], ss.getSpreadsheetTimeZone(), "yyyy-MM-dd"),
      "endDate": Utilities.formatDate(singlePlacementArray[6], ss.getSpreadsheetTimeZone(), "yyyy-MM-dd"),
      "placementAssignments": [
        {
          "placementId": parseInt(singlePlacementArray[9]),
          "active": true,
          //"sslRequired": false,
        }
      ]
    }, "6485800");

I get this vague error:

Unexpected error while getting the method or property insert on object Apiary.dfareporting.ads.

What might be wrong with the ad object?

Is it about the dates, the type?