Android Question [SOLVED] Error using Firebase Notification

[SOLVED] I'm trying to use FireBaseNotification.

I have create a new Project using Erel tutorial :
https://www.b4x.com/android/forum/t...s-firebase-cloud-messaging-fcm.67716/#content

When i run app in debug, have this error.

???


Logger connesso a: HUAWEI VKY-L09
--------- beginning of main
--------- beginning of system
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
*** Service (firebasemessaging) Create ***
** Service (firebasemessaging) Start **
Error occurred on line: 15 (FireBaseMessaging)
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.firebase.iid.FirebaseInstanceId.zza(java.lang.String)' on a null object reference
at com.google.firebase.messaging.FirebaseMessaging.subscribeToTopic(Unknown Source:131)
at anywheresoftware.b4a.objects.FirebaseNotificationsService$FirebaseMessageWrapper.SubscribeToTopic(FirebaseNotificationsService.java:130)
at order.maker.firebasemessaging._subscribetotopics(firebasemessaging.java:256)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:710)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:339)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:249)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:139)
at anywheresoftware.b4a.BA$2.run(BA.java:360)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7415)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)