Directions request failed due to REQUEST_DENIED. Google map API

import React, { Component } from 'react';
 
const divStyle = {
  marginTop:'20px',
  width: '100%',
  height:'400px'
};
 
let map,firstMarker,secondMarker;
 
class OrderMap extends Component {
  
    
    componentDidMount(){
        this.renderMap()
    }
    renderMap=()=>{
        loadScript("https://maps.googleapis.com/maps/api/js?key=ключ&callback=initMap")
 
        window.initMap=this.initMap
    }
 
    initMap=()=>{
      var directionsService = new window.google.maps.DirectionsService;
      var directionsDisplay = new window.google.maps.DirectionsRenderer;
 
         map = new window.google.maps.Map(document.getElementById('map'),
      {
        center:{lat:54.51,lng:36.25},
    zoom:13.4}
      )
      directionsDisplay.setMap(map);
      
       firstMarker = new window.google.maps.Marker({
        position: { lat: 54.513, lng: 36.269 },
        map: map,
    
      });
 
 
      window.google.maps.event.addListener(map, 'click', function(event) {
        placeMarker(event.latLng);
        calculateAndDisplayRoute(directionsService,directionsDisplay);
     });
    }
    render() {
        return (
            <div>  
              
                <div style={divStyle} id="map"></div>
            </div>
        );
    }
}
 
function loadScript(url){
    var index =window.document.getElementsByTagName("script")[0]
    var script = window.document.createElement("script")
    script.src=url
    script.async=true
    script.defer=true
    index.parentNode.insertBefore(script,index)
}
function calculateAndDisplayRoute(directionsService,directionsDisplay){
 
  directionsService.route({
    origin: firstMarker.position,
    destination: secondMarker.position,
    travelMode:'DRIVING'
  }, function(response,status){
    if(status==='OK'){
      directionsDisplay.setDirection(response);
    }else{
      window.alert('Directions request failed due to '+ status);
    }
  });
}
function placeMarker(location) {
   secondMarker = new window.google.maps.Marker({
      position: location, 
      map: map
  })
 
}
export default OrderMap;