CORS not working in rust rocket API when called from angular application

Question

I've created a simple rocket API and angular app to test things out. Rocket API works perfectly fine when called from Postman or Insomnia, but when I try to call it from angular app CORS is preventing me even though I configured CORS using rocket_cors crate. This is my rocket main function:

#[rocket::main]
async fn main() {
    let cors = CorsOptions::default()
        .allowed_origins(AllowedOrigins::all())
        .allowed_methods(
            vec![
                Method::Get,
                Method::Post,
                Method::Delete,
                Method::Put,
                Method::Patch,
                Method::Options,
            ]
            .into_iter()
            .map(From::from)
            .collect(),
        )
        .allow_credentials(true)
        .to_cors()
        .expect("error creating CORS fairing");

    let _ = rocket::build()
        //.attach(cors)
        .mount(
            "/",
            routes![get_users, get_user, create_user, update_user, delete_user],
        )
        .attach(cors)
        .register(
            "/",
            catchers![not_found, unauthorized, unprocessable_entity],
        )
        .attach(DbConn::fairing())
        .attach(AdHoc::on_ignite("Diesel migrations", run_db_migrations))
        .launch()
        .await;
}

and this is my Cargo.toml:

[dependencies]
rocket = { version = "0.5.0-rc.3", features = ["json"] }
serde = { version = "1.0.126", features = ["derive"] }
serde_json = "1.0.107"
base64 = "0.21.4"
diesel = { version = "2.0", features = ["sqlite", "r2d2"] }
rocket_sync_db_pools = { version = "0.1.0-rc", features = ["diesel_sqlite_pool"] }
diesel_migrations = "2.0"
rocket_cors = { git = "https://github.com/lawliet89/rocket_cors", branch = "master" }

I tried moving around .attach(cors) up and down, but to no avail.

This is the route:

#[get("/users")]
async fn get_users(db: DbConn) -> Result<Value, Custom<Value>> {
    db.run(|c| {
        UserRepository::get_all(c)
            .map(|users| json!(users))
            .map_err(|err|
                match err {
                    NotFound => Custom(Status::NotFound, json!({"status": "error", "reason": "Resource was not found."})),
                    _ => Custom(Status::InternalServerError, json!({"status": "error", "reason": err.to_string()}))
                }
            )
    }).await
}

This is the error message in browser:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8000/users. (Reason: CORS request did not succeed). Status code: (null).