Rect Js router stop when routes import from external file - reactjs

Question

i working by react js router (react-router-dom v4.2) and Redux together and have strange varios problem
first i say i successfully used and run this but the problems
when i use the root route as first rote in route list router stop working!!
but when i use '/' route as last route everything is ok
<Switch>
<Route path="/blog" component={Blog} />
<Route path="/users/" component={Users} />
<Route path="/" component={Home} axact />
</Switch>
when i create routes as external component and import it to app routes not work
this is my route.js codes
import React, { Component } from 'react';
import { Switch, Route } from "react-router-dom";
// import Components
import Home from './components/Home'
import Blog from './components/blog/Blog'
import Users from './components/users/Users'
class router extends Component {
render() {
return (
<div>
<Switch>
<Route path="/" component={Home} axact />
<Route path="/blog" component={Blog} />
<Route path="/users/" component={Users} />
</Switch>
</div>
);
}
}
export default router;
this is my App.js codes:
import React, { Component } from 'react';
import { getUsers } from './store/actions'
import { connect } from 'react-redux'
import { withRouter } from "react-router-dom";
import Nav from './components/navigation/Nav';
import axios from 'axios';
const userApi = "https://jsonplaceholder.typicode.com/users"
class App extends Component {
componentWillMount() {
axios.get(userApi)
.then(response => {
let users = response.data
this.props.getUserList(users)
})
.catch(error => {
console.log(error)
})
}
render() {
return (
<div className="container">
<Nav />
<Router />
</div>
);
}
}
const mapDispatchToProps = dispatch => ({ getUserList: (api) => dispatch(getUsers(api)) })
export default withRouter(connect(null, mapDispatchToProps)(App));
when i use this codes everything is ok
import React, { Component } from 'react';
import { getUsers } from './store/actions'
import { connect } from 'react-redux'
import { Switch, Route, withRouter } from "react-router-dom";
import Home from './components/Home'
import Blog from './components/blog/Blog'
import Users from './components/users/Users'
import Nav from './components/navigation/Nav';
import axios from 'axios';
const userApi = "https://jsonplaceholder.typicode.com/users"
class App extends Component {
componentWillMount() {
axios.get(userApi)
.then(response => {
let users = response.data
this.props.getUserList(users)
})
.catch(error => {
console.log(error)
})
}
render() {
return (
<div className="container">
<Nav />
<Switch>
<Route path="/blog" component={Blog} />
<Route path="/users/" component={Users} />
<Route path="/" component={Home} axact />
</Switch>
</div>
);
}
}
const mapDispatchToProps = dispatch => ({ getUserList: (api) => dispatch(getUsers(api)) })
export default withRouter(connect(null, mapDispatchToProps)(App));