Actix-web unable to send Set-Cookie

Question

So i use actix web on the backend and svelte on the frontend

This sends the cookie to the frontend

                let cookie = auth_authority.create_signed_cookie(UserClaims {
                    id: o.id,
                    role: Role::User,
                })?;
                info!("Logged in user");
                info!("{}", cookie);
                Ok(HttpResponse::Ok()
                    .cookie(cookie)
                    .json("You are now logged in"))

And this is the CORS config:

        let cors = Cors::default()
            .allowed_origin("http://localhost:3000")
            .allowed_methods(vec!["POST", "GET"])
            .allowed_headers(vec![
                header::AUTHORIZATION,
                header::CONTENT_TYPE,
            ])
            .expose_any_header()
            .supports_credentials()
            .max_age(3600);

And this is the function that fetches the data for svelte:

        const resp = await fetch("http://0.0.0.0:4000/login", {
            method: "POST",
            mode: 'cors',
            credentials: 'include',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(
                {
                    username,
                    password,
                }
            )
        })

I do not recieve the Set-Cookie header when using a web browser but when i use curl i do(Most likely caused by CORS). I can send other headers that i create but i cannot send Set-Cookie no matter what. I used the .supports_credentials() method to allow cookies but that did nothing.

Can someone guide me into a direction to solve this or does someone know how to solve it?