@ionic-native/google-maps plugin cannot work in iOS

I am using @ionic-native/google-maps plugin in ionic 3 for mobile application (Android & iOS). I am not able to load google-maps in both platform android and iOS. It always shows error message like “Cannot find name unknow”. If I try to install a lower version of plugin than it shows error message like "google-map-plugin’ cannot find or not installed in iOS. Please give some solutions for that.