Ploy line not drawing

[dulangaheshan]

I tried with the example code which provided in README.md file

render() {
  const triangleCoords = [
    {lat: 25.774, lng: -80.190},
    {lat: 18.466, lng: -66.118},
    {lat: 32.321, lng: -64.757},
    {lat: 25.774, lng: -80.190}
  ];

  return(
    <Map google={this.props.google}
        style={{width: '100%', height: '100%', position: 'relative'}}
        className={'map'}
        zoom={14}>
        <Polyline
          path={triangleCoords}
          strokeColor="#0000FF"
          strokeOpacity={0.8}
          strokeWeight={2} />
    </Map>
  )
}

but it doesn't appear on the map, im currently using below version with paid google map api key "google-maps-react": "^2.0.6", "react": "^16.13.1",

thank you