как исправить ошибкуError: Element type is invalid: expected a string (for built-in components) or a class/function

как исправить ошибку × Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.Check the render method of Context.Consumer. Ошибка происходит в index.js

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import { BrowserRouter } from "react-router-dom";
import { Provider } from 'react-redux';
import { store } from './redux/store';


ReactDOM.render(
  <BrowserRouter>
    <Provider store={store}>
      <App/>
    </Provider>
  </BrowserRouter>, document.getElementById('root')
);



serviceWorker.unregister();

store.js

import {combineReducers, createStore} from "redux";
import cinemaReducer from "./CinemaReducer";

let reducers = combineReducers({
  movie: cinemaReducer
});

export const store = createStore(reducers);