Cookie is "undefined" in Koa/Express request - ajax

Question

I'm using Koa JS framework for jwt authentication.
So basically when the user signs in, I set a jwt token (signed) to user's browser cookie, which seems to work fine as shown below (Chrome cookie settings):
(www.localhost.com instead of localhost is because I edited my hostfile, but this should have no effect in setting/getting cookies)
The problem, however, is when I send a POST request to my local Koa server, the jwt cookie is undefined. All I'm doing to verify the token is this:
routes.js
const Router = require("koa-router");
const router = new Router();
router.post(`api/authenticate`, function* () {
const jwt = this.cookies.get("jwt", { signed: true }); //jwt is undefined!!
if (!jwt)
this.throw("Invalid or expired token!");
this.status = 200;
});
//...
app.use(router.routes());
app.use(router.allowedMethods());
Here, this.cookies.get("jwt") returns undefined. The POST request is sent using AXIOS library with "withCredentials: true" header and a valid CSRF token:
authenticate.js
axios.post("api/authenticate", {}, {
headers: {
"X-Requested-With": "XMLHttpRequest",
"X-CSRF-Token": "A VALID CSRF TOKEN GENERATED BY SERVER",
"Content-Type": "application/json",
},
withCredentials: true,
});
Can anyone help me find out why this.cookies.get fails to fetch cookie from a simple POST request? I'm simply posting to my localhost, so I believe this is not a CORS problem.
What is more strange is that when I check my chrome developer tool, the "jwt" and "jwt.sig" tokens are successfully included in the request header..
Any help would be appreciated.
Update: Setting the cookie
//...
this.cookies.set("jwt", "SOME JWT GENERATED BY SERVER", {
httpOnly: true,
signed: true,
});
//...