Cross-Origin Request Blocked, even with CORSPlug

Hello, I have a Phoenix Elixir API, and a Node Js web app. When I tested the API on postman it worked great, when I tried to use it with the webb app, then it fails.
I searched on the net, and found out that I should use the CorsPlug, which is what I did.
I’ve updated both my router.ex file and the endpoint.ex file.
my router.ex file :

  ...
  pipeline :api do
    plug CORSPlug, origin: "*"
    plug :accepts, ["json"]
  end

  scope "/api", Theme01Web do
    pipe_through :api

    resources("/users", UsersController)
    ...

What does your browsers dev console say?
Recent versions of Chrome state the exact issue in the console.

(See https://stackoverflow.com/a/20039427 )