Render Expects Template to be a String

Are you sure you are using correct render/2 function? Especially as in this case you should use put_view/2 or render/3.

I don’t know I am thinking it right or not as It is a simple html page I am using render/2, In render/3 I need to pass assign

As I was rendering the user to error page so what I did is create a render function in View and render template there:

  def render("403.html", _assigns) do
    render("forbidden.html", %{})
  end

and in my authentication pipe:

case claims do
  {:ok, claims} ->
    conn
    |> put_status(200)

   _ ->
    conn
    |> put_status(403)
    |> put_view(MyAppWeb.PageView)
    |> render("403.html")
    |> halt()
end