In ASP.NET Core 6 MVC - passing list of object to controller with model object - asp.net-core-mvc

Question

I have a model class like this:
public class DataModel
{
public int CreatedBy { get; set; }
public DateTime CreatedDate { get; set; }
public List<ViewModel> ViewModel { get; set; }
}
public class ViewModel
{
public int Id { get; set; }
public string Name { get; set; }
public string Address { get; set; }
}
In ASP.NET Core 6.0 MVC, from js file posting data as shown here:
let postedModel = {
CreatedBy :null,
CreatedDate :null,
ViewModel : []
}
postedModel.CreatedBy = "some id";
postedModel.CreatedDate = "today date"
$(".form-fieldset").each(function () {
let formObject = {};
$('form').find('input').each(function (index, element) {
//In cshtml Name attribute given without form index
formObject[$(element).attr('name')] = $(element).val();
})
postedModel.ViewModel.push(formObject)
}
$.ajax({
url: '/ApiController/SaveData',
type: 'POST',
crossDomain: true,
contentType: 'application/json; charset=utf-8',
dataType: 'json',
data: JSON.stringify(postedModel),
async: false
})
My api controller looks like this:
public async Task<IActionResult> SaveData([FromBody] DataModel postedModel)
{
}
but I am getting null in the api controller.
What am I doing wrong? Please help.