Exception: The parameters (null) don't match the method signature for FormApp.Form.getItemById. (line 38, file "Code")

when I am running the script below I am getting the message - Exception: The parameters (null) don't match the method signature for FormApp.Form.getItemById. (line 38, file "Code") it has been working right so far. I do not know what happened but it started to show this error:

var ssID = "1Z7uUBnzS5zKnxGswKKNAgn2XbRunqIzQZMATDl7skoE";
var formID = "1LxORhL2WgU6teJ11ax7_HsFxhbpXbjtFXiuPH5qfEfA";

var wsData = SpreadsheetApp.openById(ssID).getSheetByName("Questions#1");
var form = FormApp.openById(formID);

function updateDropdown(id,values) {
  var item = form.getItemById(id);
  item.asListItem().setChoiceValues(values);
}

Please help to find the problem and fix it!