basereducer is not a function - Redux Toolkit with createasyncthunk

I am using redux-toolkit to acquire accessToken from MSAL and redux-persist to persist the store in localStorage. I'm getting search results in clientlisting page. When I refresh the page it was working fine. But few minutes ago it throws me an error "Error in function eval in ./node_modules/redux-persist/es/persistReducer.js:144 baseReducer is not a function" I couldn't figure where am I doing wrong

store.js

import { configureStore } from '@reduxjs/toolkit'
import usersReducer from "./userSlice";
import storage from 'redux-persist/lib/storage';
import { persistReducer, persistStore } from 'redux-persist';
const persistConfig = { key: 'root', storage, }
const persistedReducer = persistReducer(persistConfig, usersReducer)
export const store = configureStore(
  { 
    reducer: { 
      users: persistedReducer,
    }
  })
export const persistor = persistStore(store)

userSlice.js

import { useMsal } from "@azure/msal-react";
import { createAsyncThunk, createSlice } from "@reduxjs/toolkit";
import { loginRequest } from "./authConfig";
import { msalInstance } from "./pages/index";

export const fetchUsersToken = createAsyncThunk(
  "users/fetchUsersToken",
  async (dispatch, getState) => {
    try {
      const token = await msalInstance.acquireTokenSilent(dispatch)
        .then((data) => data.accessToken)
      return token
    } catch (error) {
      return error.response.data
    }
  }
);

const usersSlice = createSlice({
  name: "users",
  initialState: {
    users: null,
    loading: true
  },
  reducers: {},
  extraReducers(builder) {
    builder
      .addCase(fetchUsersToken.pending, (state, action) => {
        state.loading = true
      })
      .addCase(fetchUsersToken.fulfilled, (state, action) => {
        state.loading = false,
        state.users = action.payload
      })
      .addCase(fetchUsersToken.rejected, (state, action) => {
        state.loading = false

      });
  }
})

export default usersSlice.reducer;

index.js

import React from "react"
import { Provider, useDispatch } from "react-redux";
import {persistor, store} from "../../store";
import Footer from "../Footer"
import { createTheme, ThemeProvider } from "@mui/material/styles"
import { PersistGate } from 'redux-persist/integration/react';
// Global styles and component-specific styles.

//For changing default blue color for mui text-fields
const theme = createTheme({
  palette: {
    primary: { main: "#000000" },
  },
})

const Layout = ({ children }) => (
  <div>
    <ThemeProvider theme={theme}>
      <Provider store={store}>
        <PersistGate loading={null} persistor={persistor}>
          {children}
          <Footer/>
        </PersistGate>
      </Provider>
    </ThemeProvider>
  </div>
)

export default Layout

LandingPage.js ( where I'm dispatching the action.)

const request = {
  ...loginRequest,
  account: accounts[0]
}
store.dispatch(fetchUsersToken(request))

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