$session prop token is not defined even if it is set on the browser (sapper/svelte app deployed on Netlify - Nodejs app deployed on heroku)

[work-state]

login POST request

  async function login(method, token, api_url, path, cred) {
	  const opts = {
		  method,
		  headers: {
			  Accept: "application/json, text/plain, */*",
			  "Content-Type": "application/json",
			  cookie: `ts_09=${token}`,
		  },
		  credentials: "include",
	  };
	  if (cred) {
		  opts.body = JSON.stringify(cred);
	  }
	  let url = new URL(`${api_url}/api/${path}`);

	try {
		const res = await fetch(url, opts);
		const data = await res.json();
		if (res.status !== 200) throw data;
		try {
			return data;
		} catch (ex) {
			return data;
		}
	} catch (ex) {
		throw ex;
	}
}

login Route, which at the end I send to the browser a cookie that contains a token

router.post("/log", async (req, res) => {
	try {
		const { email, password } = req.body;
		const user = await User.verifyCredentials(email, password);
		const token = await user.generateAuthToken();
		res
		    .cookie("ts_09", token, {
			    httpOnly: process.env.NODE_ENV === "production" ? false : true,
			    secure: process.env.NODE_ENV === "production" ? true : false,
			    maxAge: 24 * 60 * 60 * 1000,
		    })
		    .json("done");
	} catch (err) {
		res.json(err);
	}
});

sapper-app/src/server.js

polka()
	.use(
		compression({ threshold: 0 }),
		sirv("static", { dev }),
		cookieParser(),
		(req, res, next) => {
			const token = req.cookies["ts_09"];
			const profile = token ? jwt.decode(token) : false;
			return sapper.middleware({
				session: () => {
					return {
						authenticated: !!profile,
						profile,
						token,
					};
				},
			})(req, res, next);
		}
	)

When I try to sign in with credentials, it sends a post request, then performs a check, and at the end of it a cookie is sent from backend to the browser. In Dev Tools I can see the stored token, but when I try to console log the token it shows me "undefined"

sapper-app/src/routes/index.svelte

<script>
	import { stores } from "@sapper/app";

	const { session } = stores();

	console.log($session); // output : {authenticated: false, profile: false, token: undefined}
</script>

i don't know exactly what i missed, but locally it works fine