Estou fazendo um chat no meu APLICATIVO mas assim que eu abro a tela APARECE um erro ALGUÉM ME AJUDA pfvr😔 [fechada]

com.google.firebase.database.DatabaseException:
Not a direct subclass of Genericlypelndicator: class
com.google.firebase.database.GenericTypelndicator
at
com.google.firebase.database.core.utilities.encoding.Custom
ClassMapper.convertloCustomClass(com.google.firebase:fire
base-database@@19.0.0:103)
at
com.google.firebase.database. DataSnapshot.getValue(com.go
ogle.firebase:firebase-database@@19.0.0:229)
at com.myLGKMODS157.c.onChildAdded(Unknown Source)
at
com.google.firebase.database.core.ChildEventRegistration.fire
Event(com.google.firebase:firebase-database@@19.0.0:79)
at
com.google.firebase.database.core.view.DataEvent.fire(com.g
0ogle.firebase:firebase-database@@19.0.0:63)
at com.google.firebase.database.core.view.EventRaiser
$1.run(com.google.firebase:firebase-database@@19.0.0:55)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:
7325)
at java.lang.reflect.Method.invoke (Native Method)
at com.android.internal.os.Zygotelnit
$MethodAndArgsCaller.run(Zygotelnit.java:1230)
at com.android.internal.os.zygotelnit.main(Zygotelnit.java:
1120)