B4R Question Problem with pushing data to firebase realtime database...

Sub Process_Globals
    Public Serial1 As Serial
    Private wifi As ESP8266WiFi
    Dim timer1 As Timer
    Dim uid As Long
    Dim esp As ESP8266extras
    Dim bc As ByteConverter
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")
    uid=esp.UniqueID
    If wifi.Connect2("****","****") Then
        Log("Connected to router.")
        timer1.Initialize("timer1_Tick",2000)
        timer1.Enabled=True
    Else
        Log("Failed to connect to router.")
        Return
    End If

End Sub
Sub timer1_tick
    Dim datetime As String="26/12/2018,18:54:00"
    Dim otemp As Float=Rnd(20,30)
    Dim o As String=NumberFormat(otemp,1,2)
    Dim atemp As Float=Rnd(20,30)
    Dim a As String=NumberFormat(atemp,1,2)
    Dim u As String=uid
    Dim id As String=JoinStrings(Array As String("https://***.firebaseio.com/",u,".json"))
    Dim data As String=JoinStrings(Array As String("'",datetime,",",o,",",a,"'"))
    Log(id)
    Log(data)
    HttpJob.Initialize("")
    HttpJob.Post(id,data)
End Sub

Sub JobDone (Job As JobResult)
    Log("*******************************")
    Log("JobName: ", Job.JobName)
    If Job.Success Then
       
        Log("Response: ", bc.SubString2(Job.Response, 0, Min(200, Job.Response.Length))) 'truncate to 200 characters
    Else
        Log("ErrorMessage: ", Job.ErrorMessage)
        Log("Status: ", Job.Status)
        Log(Job.Response)
    End If
End Sub

https://***.firebaseio.com/12615289.json
26/12/2018,18:54:00,28.00,29.00
*******************************
JobName:
ErrorMessage:
Status: 400
{
  "error" : "Invalid data; couldn't parse JSON object, array, or value."
}

Sub btnSEND_Click
  
    Dim j As HttpJob
    j.Initialize("",Me)
  
    Dim DT As String=DateTime.Date(DateTime.Now)&","&DateTime.Time(DateTime.Now)
    Dim otemp As Float=Rnd(20,30)
    Dim o As String=NumberFormat(otemp,1,2)
    Dim atemp As Float=Rnd(20,30)
    Dim a As String=NumberFormat(atemp,1,2)
    Dim u As String="12345678"
    Dim id As String="https://***b.firebaseio.com/"&u&".json"
    Dim data As String="{"& $"""$&"Value"&$"""$&":"& $"""$&DT&","&o&","&a& $"""$&"}"
    Log(data)
    j.PostString(id,data)
    j.Release
End Sub

Dim j As HttpJob
    j.Initialize("",Me)
    j.Download("https://***.firebaseio.com/12345678.json")
    Wait For (j) jobdone (j As HttpJob)
    If j.Success Then
        'Log(j.GetString)
        Dim s As String=j.GetString
        Dim parser As JSONParser
        parser.Initialize(s)
        Dim root As Map = parser.NextObject
        Dim FirstValue As String = root.Get("-LUiTbdp89H7EqqBUDCm")
        Dim i As Int

        Dim otemp(root.size) As String
        Dim atemp(root.size) As String
        Dim dt(root.size) As String
        Dim tm(root.size) As String
        For Each Key As String In root.Keys
           
            Dim list1 As List
            list1.Initialize
            list1.Add (root.Get(Key))
            Dim map1 As Map
            map1 = list1.Get(0)
            Dim d As String=map1.GetValueAt(0)
            Log(d)
            Dim temp(4) As String=Regex.Split(",",d)
            dt(i)=temp(0)
            tm(i)=temp(1)
            otemp(i)=temp(2)
            atemp(i)=temp(3)
            i=i+1
           
        Next

       
    Else
        Log("Error:" &j.ErrorMessage)
       
    End If
    j.Release
   
   
End Sub

{"-LUiTbdp89H7EqqBUDCm":{"Value":"12/27/2018,12:34:26,28,26"},"-LUiTsTmgH5MMRwe_-Be":{"Value":"12/27/2018,12:35:36,24,26"},"-LUiXlocwfiQFhPqMnC2":{"Value":"12/27/2018,12:52:36,29,24"},"-LUiZ0VhxFzQTSFW2q1i":{"Value":"12/27/2018,12:58:03,23,23"},"-LUiZ5-nnrthMgBBtUdL":{"Value":"12/27/2018,12:58:22,20,20"},"-LUjDwJMb8E20WST3b6M":{"Value":"12/27/2018,16:05:33,23,26"},"-LUjDyjjYuH5lAWgJgor":{"Value":"12/27/2018,16:05:44,27,25"},"-LUjGeZBqyJLuiOjeTio":{"Value":"12/27/2018,16:17:28,24,25"},"-LUjGjd64loOAwO3U1ee":{"Value":"12/27/2018,16:17:49,22,21"}}

12/27/2018,12:34:26,28,26
12/27/2018,12:35:36,24,26
12/27/2018,16:17:28,24,25
12/27/2018,12:52:36,29,24
12/27/2018,16:17:49,22,21
12/27/2018,12:58:03,23,23
12/27/2018,16:05:33,23,26
12/27/2018,16:05:44,27,25
12/27/2018,12:58:22,20,20