redux-localstorage-simple | Save and load Redux state to and from LocalStorage | Storage library

It looks like you're not actually using the correct rendering:

1. You don't render your application wrapped by Provider, nor Router but App directly (check your ReactDOM.render(...) line);
2. You are attempting to mount your React application on a non DOM element... (same line, second argument).

Provider is a higher-order component provided by React Redux that lets you bind Redux to React.

As per the documentation of redux: https://redux.js.org/advanced/usagewithreactrouter

You need to

From redux-thunk

Redux Thunk middleware allows you to write action creators that return a function instead of an action

So it means that it doesn't handle your promises. You have to add redux-promise for promise supporting

The default export is a middleware function. If it receives a promise, it will dispatch the resolved value of the promise. It will not dispatch anything if the promise rejects.

The differences between redux-thunk vs redux-promise you can read here