Authorization Failure when sending Notification

Question

I am trying to send Notification to a android device through Azure Notification Hub but i am getting Unauthorized(status code 401).Herre is the code for sending Notification.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Text.Json;
using System.Runtime.Remoting.Messaging;
using System.Net.Http.Json;
using System.Text.Json.Serialization;
using Newtonsoft.Json;
using System.Net.Http.Headers;
using System.Web;
using System.Security.Policy;
using System.Net.Mime;
using Microsoft.SqlServer.Server;

namespace TestSend
{
    internal class Program
    {
        static void Main(string[] args)
        {
            PostMessage().GetAwaiter().GetResult();
            Console.ReadLine();
        }
        static async Task PostMessage()
        {
            var client = new HttpClient();
            var se = (int)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds + 300;
            var my_uri = HttpUtility.UrlEncode("https://irmtnh.servicebus.windows.net/IRMTNotificationHub").ToLower();
            var hash_string = $"my_uri\nse";
            var sha_signature = HttpUtility.UrlEncode(Convert.ToBase64String(EncryptString(hash_string)));
            var Param = HttpUtility.UrlEncode("api-version:2015-04");
            var auth = $"SharedAccessSignature sig={sha_signature}&se={se}&skn=DefaultFullSharedAccessSignature&sr={my_uri}";
            //client.DefaultRequestHeaders.Add("Content-Type", "application/json");
            client.DefaultRequestHeaders.Add("ServiceBusNotification-Format", "gcm");
            client.DefaultRequestHeaders.Add("Authorization", auth);
           
            // Set the body as appropriate
            var requestBody  = new
            {
                notification = new
                {
                    title = "Notification Hub Test Notification",
                    body = "This is a Test."
                },
                data = new
                {
                    property1 = "value1",
                    property2 = 42
                }
            };

            // Convert the message to JSON
            var jsonMessage = JsonConvert.SerializeObject(requestBody);
            
            var bodyContent = new StringContent(jsonMessage,Encoding.UTF8,"application/json");
          
            var url = "https://irmtnh.servicebus.windows.net";
           
           client.BaseAddress = new Uri(url);
          // var FullAddress = client.BaseAddress.ToString() ;
            var response = await client.PostAsync("/IRMTNotificationHub/messages/?api-version=2015-04", bodyContent);    
            Console.WriteLine(Convert.ToInt32(response.StatusCode));
           Console.WriteLine(response.Headers.ToString());
            Console.WriteLine(response.ReasonPhrase);
            Console.WriteLine(response.RequestMessage.ToString());
        }
       
        static byte[] EncryptString(string hash_string)
        {
            var key = Convert.FromBase64String("my key");
            var to_sign = Encoding.UTF8.GetBytes(hash_string);
            using (var hmac = new HMACSHA256(key))
            {
                return hmac.ComputeHash(to_sign);
            }
        }
    }
}

Answer 1

The error message "Unauthorized (status code 401)" indicates that the authorization failed. It seems that the issue is with the authorization header. You can try to check the following things:

Verify that the shared access signature (SAS) token is correct, correctly encoded, has not expired, is for the correct resource, has the correct permissions, is for the correct endpoint and API version and namespace. Also, verify that it's setup for the correct hub, entity, and policy.

Can you please check these items and let us know if these suggestions resolve the issue? If not, please let us know so we can assist you further.