React app always going to home route after receiving the response from the backend(node.js)

Question

after I receive the response from the backend and based on it trying to redirect to a different route but no matter what i do the app redirects to the signin route and display my http request on the link although it is a post request

i tried getting the response and do nothing with it (i did only fetch (no then) and got the response ) it worked but when try to go to different the problem happens and i know for sure that response is getting back

onSubmitSignIn = () => {
    fetch('http://localhost:3000/signin' , {
      method: 'post' , 
      headers: {'Content-Type': 'application/json'},
      body: JSON.stringify({
        email: this.state.signInEmail,
        password: this.state.signInPassword
      })
    })
    .then(response => response.json())
    .then(data => {
      if (data === 'success') {
        this.props.onRouteChange('home');
      }
    })    
  }





onRouteChange= (route) => {
    if (route==='signout'){
      this.setState({isSignedIn:false})
    }
    else if (route ==='home') {
      this.setState({isSignedIn:true})
    }
    this.setState({route:route})
  }

  render() {
  return (
    <div className="App">
      <Navigation  isSignedIn={this.state.isSignedIn} onRouteChange = {this.onRouteChange}/>
      <ParticlesBg color="#282c34" num={200} type="cobweb" bg={true} />
      { this.state.route === 'home' ?
         <div> <Logo />
         <Rank />
         <ImgLinkForm onInputChange={this.onInputChange} onSubmit={this.onSubmit}/>
         <Facerec box={this.state.box} imageurl={this.state.imageurl} />
         </div>
       
       :
      (this.state.route === 'signin'  ? <Signin  onRouteChange = {this.onRouteChange} />
       : <SignUp loadUser={this.loadUser} onRouteChange = {this.onRouteChange} />
           )
      }
    </div>
  );}