How to fix “the trait `Factory<_, _, _>` is not implemented for `fn(Json) -> impl std::future::Future {auth}” error in RUST using ACTIX?

Question

I have this simple code:

use actix_web::{get, post, web, App, HttpResponse, HttpServer, Responder};
use serde::{Deserialize, Serialize};
use serde_json::{json};
u