Authorization return {} and not setting cookie

[hayatiuyun]

Does anyone know what's this error means {} after successfull signIn in auth.js with nextauth?

I'm using NextAuth.js with a custom CredentialsProvider. The authorizeand jwt callbacks work fine, but the session cookie isn't set, and the session callback doesn't trigger. The signIn return {} Here's my configuration:

import NextAuth from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";

export default NextAuth({
  providers: [
    CredentialsProvider({
      id: "jid",
      name: "jid",
      credentials: { 
someCredentials: {}
 },
      authorize: async (credentials) => {
        if (!!credentials) {
          return {
            ...credentials
          };
        }
        return null;
      },
    }),
  ],
  callbacks: {
    async jwt({ token, user }) {
      if (user) {
        token = user
      }
      return token;
    },
    async session({ session, token }) {
      session = token;
      return session;
    },
  },
  secret: //secret,
});

What could be causing this issue? How I can fix it?