Unable to clear input field automatically after clicking on submit (React)

I am new to react, and I am having trouble trying to make the input field clear automatically after clicking the submit button. I believe that I have made the component a fully controlled one by react, where the input value is solely dependent on the state's input. Hope someone is able to help. Been stuck for a few hours now. Really not sure where I've gone wrong. Thanks!

import React, { Component } from 'react'; 
import './App.css';
import Axios from 'axios';
import { Link, BrowserRouter, Route} from 'react-router-dom';
import reviews from './Screen/Reviews'; 

class App extends Component{

  constructor() {
    super();

    this.state = {
      movieName: '',
      setReview: ''
    };

    this.onMovieChange = this.onMovieChange.bind(this);
    this.onReviewChange = this.onReviewChange.bind(this);
    this.submitReview = this.submitReview.bind(this);

  }
  onMovieChange(e) {
    this.setState({
      movieName: e.target.value
    });
  }
  onReviewChange(e) {
    this.setState({
      setReview: e.target.value
    });
  }
  submitReview(e) {
    e.preventDefault();
    const movieName = this.state.movieName;
    const movieReview = this.state.setReview;
    Axios.post('http://localhost:3001/api/insert',
    {movieName: movieName, movieReview: movieReview}).then(()=>
    {
      alert('Insert successfully');  
    }
    ) 
    this.setState({
      movieName: '',
      setReview: ''
    })
  }
    
  render() {
    return (
      <BrowserRouter>
      <div className="form">
      <form   >
        <ul className="form-container">
          <li>
            <h2>Movie Review</h2>
          </li>  
          <li>
            <label htmlFor="movieName">
            Movie Name {" "}
            </label>
            <input className="movieName" type="movieName" name="movieName" id="movieName" onChange={this.onMovieChange}>
            </input>
          </li>
          <li>
            <label htmlFor="review">Review{" "}</label>
            <input className="review" type="review" id="review" name="review" onChange={this.onReviewChange}>
            </input>
          </li>
          <li> 
          <button onClick={this.submitReview}  type="submit" className="button-register-registration ">Submit</button>

          </li>

          <li>
            <Link to="/review" className="button-register-for-sign-in" ><h4>Go to reviews</h4></Link>
          </li>
        </ul>
      </form>
      <main>
        <div className="content">
        <Route path={"/review"} component={reviews}></Route> 
        </div>
      </main>
      </div>
    </BrowserRouter>
    );
  }

}

you are treating input as an uncontrolled component, so react cannot control its value and hence not sync with its state. So make your input controlled by updating as below

  <input className="movieName" type="movieName" name="movieName" id="movieName" onChange={this.onMovieChange} value={this.state.movieName}>