Typescript TS2339：类型{}上不存在属性消息

我正在使用Reaction-Redux和TypeScrip，但收到错误:

TS2339:类型{}上不存在属性消息

import type { RootState } from "../store.ts";
import { fetchBaseQuery } from '@reduxjs/toolkit/query'
import type {
  BaseQueryFn,
  FetchArgs,
  FetchBaseQueryError,
} from '@reduxjs/toolkit/query/react'
import { createApi } from "@reduxjs/toolkit/query/react";

const baseQuery = fetchBaseQuery({
    baseUrl: 'http://localhost:3500/api/v1/',
    credentials: 'include',
    prepareHeaders: (headers: Headers, { getState }) => {
        const token: string|null = (getState() as RootState).auth.token
        if (token) {
            headers.set("authorization", `Bearer ${token}`)
        }
        return headers
    }
});

const baseQueryWithReauth: BaseQueryFn<
    string | FetchArgs,
    unknown,
    FetchBaseQueryError
> = async (args, api, extraOptions) => {
    const result = await baseQuery(args, api, extraOptions)
    console.log(result?.data?.message.AT);
    return result
}

我怎样才能得到result.data.message.AT分而不会出错？

我从后端返回数据如下:

res.status(200)
  .send({
    success: true,
    message: { AT: accessToken } }
  );