Using VB.NET to sent notification to android emulator get error 401

Question

I'm writing VB.NET code to send notification to android Emulator. I can successfully send test message from the firebase control. However, it failed when I tried to send message via VB.NET code in my local machine and get error "The remote server returned an error: (401) Unauthorized".

I have tried looking at the following link: FCM (Firebase Cloud Messaging) Push Notification with Asp.Net and following the instructions but it still not working.

Here is my code:

Imports System.Net
Imports Newtonsoft.Json

Public Class Notification

    Public Sub SendNotification(ByVal deviceIDList As List(Of String), ByVal title As String, ByVal bodyMsg As String)

        Dim fcmPath As String = "https://fcm.googleapis.com/fcm/send"
        Dim serverKey As String = "AIzaxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxoCAeI"
        Dim senderID As String = "35xxxxxxx37"

        Dim request As HttpWebRequest = CType(HttpWebRequest.Create(fcmPath), HttpWebRequest)
        With request
            .Method = "POST"
            .ContentType = "application/json"
            .Headers.Add(String.Format("Authorization: key={0}", serverKey))
            .Headers.Add(String.Format("Sender: id={0}", senderID))
        End With

        Using streamWriter = New StreamWriter(request.GetRequestStream())
            Dim webObject As New WebRequestFcmData
            With webObject
                .registration_ids = deviceIDList
                .notification.title = title
                .notification.body = bodyMsg
                .notification.content_available = True
                .notification.sound = "default"
                .notification.priority = "high"
            End With
            Dim body = JsonConvert.SerializeObject(webObject)
            With streamWriter
                .Write(body)
                .Flush()
                .Close()
            End With
        End Using
        Dim httpResponse = CType(request.GetResponse(), HttpWebResponse)
        Using streamReader As New StreamReader(httpResponse.GetResponseStream)
            Dim result = streamReader.ReadToEnd
        End Using
    End Sub
End Class

Public Class WebRequestFcmData
    Public Property registration_ids As List(Of String)
    Public Property notification As New NotificationData
End Class

Public Class NotificationData
    Public Property body As String
    Public Property content_available As Boolean
    Public Property priority As String
    Public Property title As String
    Public Property sound As String
End Class

The error occurred at the line:

Dim httpResponse = CType(request.GetResponse(), HttpWebResponse)

Here is the server key and sender ID that I use:

Updated: I tried sending web request from Postman application and it also gave the same error (401: Unauthorized) as shown in the figure below:

which error do you get? you should at least write Dim response As HttpWebResponse = CType(request.GetResponse(), HttpWebResponse) and use response instead of httpResponse — nbk, Apr 09 '19 at 21:24
I got the error "The remote server returned an error: (401) Unauthorized." It still occur even though I fixed the code as you mentioned. — Pawich S., Apr 10 '19 at 03:13
401 means your account data is not valid. you should check id and server key — nbk, Apr 10 '19 at 08:29
OK. I have made a silly mistake by looking for the key in the wrong place. Now, I found the solution and updated the answer. Thank you nbk for your help :D — Pawich S., Apr 11 '19 at 04:22

score 0 · Accepted Answer · answered Apr 11 '19 at 04:20

OK. I made a silly mistake by using API Key which is not actual Server key. Even though I have read that I should go to cloud messaging tab in project setting, I misunderstood that I have to look in cloud messaging tab in the side bar which is wrong. Here is the step where I found server key: