title: Error 401 'INVALID_KEY_TYPE' con FireBase y c#
body: <p>I am implementing c # with FireBase, it sends me error 401 'INVALID_KEY_TYPE'</p>
  
  <pre><code>enter code here
  </code></pre>
  
  <p>private static Uri FireBasePushNotificationsURL = new Uri("<a href="https://fcm.googleapis.com/fcm/send" rel="noreferrer">https://fcm.googleapis.com/fcm/send</a>");
          private static string ServerKey = "AIzaSyA9fL8lPyxcrngIDDsDeUbq9sPTkavXXXX";</p>
  
  <pre><code>    public static async Task&lt;bool&gt; SendPushNotification(string deviceTokens, string title, string body, object data)
      {
          bool sent = false;
  
          if (deviceTokens.Count() &gt; 0)
          {
              //Object creation
  
              var messageInformation = new 
              {
                  to = "fZ0EyxU-tsk:APA91bE3-qo4DwL9phteDJC8pG6iLdr-YSSl-N_2SJne3U6eyUhmEuZNQhJi0YM-XXXXXX",
                  priority = "high",
                  content_available = true,
                  notification = new
                  {
                      body = "Test",
                      title = "Test miguel",
                      badge = 1
                  },
              };
  
              //Object to JSON STRUCTURE =&gt; using Newtonsoft.Json;
              string jsonMessage = JsonConvert.SerializeObject(messageInformation);
  
              //Create request to Firebase API
              var request = new HttpRequestMessage(HttpMethod.Post, FireBasePushNotificationsURL);
  
              request.Headers.TryAddWithoutValidation("Authorization", "key=" + ServerKey);
              request.Content = new StringContent(jsonMessage, Encoding.UTF8, "application/json");
  
              HttpResponseMessage result;
              using (var client = new HttpClient())
              {
                  result = await client.SendAsync(request);
                  sent = sent &amp;&amp; result.IsSuccessStatusCode;
              }
          }
  
          return sent;
  
      }
  </code></pre>