OnPost handler not being called

I am trying to call an onpost method from a razor page, however I am getting 'page not found' on https://localhost:44873/MyPage/create

Razor page:

      @page"{handler?}"

            //display stuff

      <formasp-page-handler="create"method="post">

      <inputtype="hidden"name="id" value=@Html.DisplayFor(modelItem => item.Id) />

      <buttonclass="btn btn-default">Create</button>

      </form>

Which generates:

    <form method="post" action="/MyPage/create"> //I have tried create and Create
    <input type="hidden" name="id" value="2012">
    <button class="btn btn-default">Create</button></form>

In PageModel:

       public async Task<IActionResult> OnPostCreateAsync(int? id)

        {

                     \\Breakpoint that is never hit

            var myobject =await _context.MyObject.FindAsync(id);

            if (ModelState.IsValid)

            {

                return NotFound();

            }

            // Do stuff

            return Page();

        }