How do I set security header for phoenix elixir application.

I used this plug, but its not working.

defmodule Provider.Plugs.SecurityHeaders do
  @moduledoc """
  put response header for security
  """
  import Plug.Conn

  def init(opts), do: opts

  def call(conn, _opts) do
    conn
    |> put_resp_header("x-frame-options", "DENY")
    |> put_resp_header("content-security-policy", "frame-src 'self'; frame-ancestors 'none'")
    |> put_resp_header("x-content-type-options", "nosniff")
    |> put_resp_header("referrer-policy", "no-referrer")
    |> put_resp_header("cross-origin-opener-policy", "same-origin")
    |> put_resp_header("cross-origin-embedder-policy", "unsafe-none")
    |> put_resp_header("cross-origin-resource-policy", "same-origin")
    |> put_resp_header("strict-transport-security", "max-age=31536000; includeSubDomains")
  end
end

pipeline :browser do
    plug(:accepts, ["html"])
    plug(:fetch_session)
    # plug :fetch_flash
    plug(:fetch_live_flash)
    plug(:put_root_layout, {Provider.LayoutView, :root})
    plug(:protect_from_forgery)
    plug(:put_secure_browser_headers)
    plug(:load_information)
    plug(:fetch_current_user)
    plug(Provider.Plugs.CSP)
    plug(Provider.Plugs.SecurityHeaders)
  end