Android Question Notification error

Message arrived
Message data: {body=Hello Students, sound=default, title=mySchool}
b4xpages_getmanager (java line: 56)
java.lang.ClassCastException: java.lang.Object cannot be cast to b4a.mySchool.b4xpagesmanager
at b4a.mySchool.b4xpages._getmanager(b4xpages.java:56)
at b4a.mySchool.b4xpages._mainpage(b4xpages.java:100)
at b4a.mySchool.firebasemessaging._fm_messagearrived(firebasemessaging.java:162)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:213)
at anywheresoftware.b4a.BA$1.run(BA.java:352)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6138)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:893)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:783)

Click to expand...

Sub fm_MessageArrived (Message As RemoteMessage)
    Log("Message arrived")
    Log($"Message data: ${Message.GetData}"$)
    
    n.Initialize
    n.Initialize2(n.IMPORTANCE_DEFAULT)
    n.Icon = "icon"
    n.OnGoingEvent = False
    'n.Sound = True
    n.AutoCancel = True
    
    n.SetInfo(Message.GetData.Get("title"), Message.GetData.Get("body"), Main)
    
    B4XPages.MainPage.BadgeNumber = B4XPages.MainPage.BadgeNumber + 1
    n.Notify(1)
    msgs = msgs + 1
    
    B4XPages.MainPage.reloadSystemMenu(B4XPages.MainPage.BadgeNumber)
    
End Sub