Cant write data to firebase database Android

I am trying to send test data to my firebase database. In android studio I chose Tools > Firebase > Assistant FB > Realtime Database > Connect your app to Firebase(Connected) > Add the realtime database to your app(dependencies set up correctly).

Then I add sample code in my activity:

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");

myRef.setValue("Hello, World!");

I set the rules in firebase:

{
  "rules": {
    ".read": true,
    ".write": true
  }
}

But the data does not add to the realtime database. Maybe I need some permission? In logcat AS nothing error

UPD:

not add data

    private DatabaseReference mDatabase;
 mDatabase = FirebaseDatabase.getInstance().getReference();
        mDatabase.child("message").setValue("Hello, World!");

not add data too

Message mess = new Message("hello");
        mDatabase.child("message").setValue(mess);

class Message

@IgnoreExtraProperties
public class Message {

    public String mes;

    public Message(){}

    public Message(String mes) {this.mes = mes;}

}