NextAuth session callback does not trigger - next.js

Question

I deployed a Nextjs(v13) app with AWS Amplify and using NextAuth(v4.17.0). I'm using CredentialsProvider with a custom server. All works great in development environment, but in production the session callback doesn't fire and the session is empty, even if the token gets created in the database
/page/api/auth/[...nextauth].tsx disregard the console logs lol
import NextAuth from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import jwt_decode from "jwt-decode";
import { TokenInfo } from "../../../components/types/auth_types";
async function refreshAccessToken(token) {
try {
console.log("BUT WHY?");
const res = await fetch(
`${process.env.NEXT_PUBLIC_API_URL}/api/token/refresh/`,
{
method: "POST",
body: JSON.stringify({refresh: token.refreshToken}),
headers: {"Content-Type": "application/json"},
}
);
if (!res.ok) throw "refreshError";
const responseJson = await res.json();
return {
...token,
accessToken: responseJson.access,
}
} catch(error) {
return {
...token,
error: "RefreshAccessTokenError",
}
}
}
export const authOptions = {
providers: [
CredentialsProvider({
id: "credentials",
name: "Credentials",
credentials: {
email: { label: "Username", type: "text", placeholder: "" },
password: { label: "Password", type: "password" }
},
async authorize(credentials, req) {
const userCredentials = {
email: credentials.email, password: credentials.password
};
try {
const res = await fetch(
`${process.env.NEXT_PUBLIC_API_URL}/api/token/`,
{
method: "POST",
body: JSON.stringify(userCredentials),
headers: {"Content-Type": "application/json"},
credentials: "include",
}
);
console.log("res", res);
if (res.ok) {
const responseJson = await res.json();
console.log("resJson", responseJson);
const tokenInfo: TokenInfo = jwt_decode(responseJson.access);
console.log("tokenInfo", tokenInfo);
return {
id: tokenInfo.user_id.toString(),
email: tokenInfo.email,
firstName: tokenInfo.first_name,
lastName: tokenInfo.last_name,
isStaff: tokenInfo.is_staff,
accessToken: responseJson.access,
refreshToken: responseJson.refresh,
};
}
return null;
} catch(e) {
return null;
}
}
})
],
callbacks: {
async jwt({ token, account, user }) {
if (account && user) {
console.log("got into token", user);
token.firstName = user.firstName;
token.lastName = user.lastName;
token.refreshToken = user.refreshToken;
token.accessToken = user.accessToken;
}
if (token.accessToken) {
console.log("got in this if instead")
const decodedToken: TokenInfo = jwt_decode(token.accessToken);
if (Date.now() < decodedToken.exp * 1000) {
console.log("got here, returned properly");
return token;
}
}
console.log("got here, not properly, why?");
return await refreshAccessToken(token);
},
async session({ session, token }) {
console.log("getting session");
session.user.firstName = token.firstName;
session.user.lastName = token.lastName;
session.accessToken = token.accessToken;
console.log("sess", session);
return session;
}
},
secret: process.env.NEXT_AUTH_SECRET,
session: {
maxAge: 2 * 24 * 60 * 60, // two days
}
};
export default NextAuth(authOptions);
I have searched as best as I could and couldn't find anything that I didn't do already.
My understanding is I don't need to set session: { strategy: "jwt"} since that's the default.
I have NEXT_AUTH_SECRET="mysecret", NEXT_PUBLIC_API_URL="https://www.backend_domain.com" and NEXTAUTH_URL="https://www.frontend_domain.com" set properly in .env.production and the API calls succeed, as well as the NextAuth calls return 200 status code, no errors in Amplify logs
Edit 1:
If I navigate to /api/auth/signin/credentials and use the default UI for login, the session gets created successfully