Android Question firebase messaging sends only to one device

[Makumbi]

Please help after setting up firebase message wen i send the message. only one phone which gets the message please help

#Region  Service Attributes
    #StartAtBoot: False
    
#End Region

Sub Process_Globals
    Private fm As FirebaseMessaging
End Sub

Sub Service_Create
    fm.Initialize("fm")
End Sub

Public Sub SubscribeToTopics
    fm.SubscribeToTopic("general") 'you can subscribe to more topics
    
End Sub

Sub Service_Start (StartingIntent As Intent)
    If StartingIntent.IsInitialized Then fm.HandleIntent(StartingIntent)
    Sleep(0)
    Service.StopAutomaticForeground 'remove if not using B4A v8+.
End Sub

Sub fm_MessageArrived (Message As RemoteMessage)
    Log("Message arrived")
    Log($"Message data: ${Message.GetData}"$)
    Dim n As Notification
    n.Initialize
    n.Icon = "icon"
    n.SetInfo(Message.GetData.Get("title"), Message.GetData.Get("body"), Main)
    n.Notify(1)
End Sub

Sub Service_Destroy

End Sub

Sub AppStart (Args() As String)
    SendMessage("general", "Kabojja Junior School", "Sports Day is Tommorrow please come all!!!!")
    'SendMessage("0772433637", "Kabojja Junior School", "Hello goodwork man sula Joweria!!!!")
    StartMessageLoop
End Sub

Private Sub SendMessage(Topic As String, Title As String, Body As String)
    Dim Job As HttpJob
    Job.Initialize("fcm", Me)
    Dim m As Map = CreateMap("to": $"/topics/${Topic}"$)
    Dim data As Map = CreateMap("title": Title, "body": Body)
    m.Put("data": data)
    Dim jg As JSONGenerator
    jg.Initialize(m)
    Job.PostString("https://fcm.googleapis.com/fcm/send", jg.ToString)
    Job.GetRequest.SetContentType("application/json")
    Job.GetRequest.SetHeader("Authorization", "key=" & API_KEY)
End Sub


Sub JobDone(job As HttpJob)
    Log(job)
    If job.Success Then
        Log(job.GetString)
    End If
    job.Release
    StopMessageLoop '<-- non ui app only
End Sub

 

[Erel]

How will you identify each device? You can let each device subscribe to a unique topic.