I am trying to add notification services to my app using FCM and tutorial given on https://www.simplifiedcoding.net/firebase-cloud-messaging-android/ Everything has done and
In your Gradle file all the versions of google-play-service and firebase should use the same version.
As you are using :
compile 'com.google.android.gms:play-services-drive:10.0.1'
You should use :
compile 'com.google.firebase:firebase-messaging:10.0.1' // and not 9.2.1
compile 'com.google.firebase:firebase-messaging:10.0.1'