FirebaseX exception in ionic project

I’m working with FirebaseX in an Ionic 4 project and i get this error.

NullInjectorError: No provider for FirebaseX

How do I load this service in the appModule.ts?
If i just put FirebaseX in the provider section i get this error

Invalid provider for the NgModule 'AppModule'

Please help.

FirebaseX – https://github.com/dpa99c/cordova-plugin-firebasex

Thanks.

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