diff --git a/TLSharp.Core/Network/MtProtoSender.cs b/TLSharp.Core/Network/MtProtoSender.cs
index d46a68e..8929760 100644
--- a/TLSharp.Core/Network/MtProtoSender.cs
+++ b/TLSharp.Core/Network/MtProtoSender.cs
@@ -293,6 +293,10 @@ namespace TLSharp.Core.Network
                     var dcIdx = int.Parse(resultString);
                     throw new UserMigrationException(dcIdx);
                 }
+                else if (errorMessage == "PHONE_CODE_INVALID")
+                {
+                    throw new InvalidPhoneCodeException("The numeric code used to authenticate does not match the numeric code sent by SMS/Telegram");
+                }
                 else
                 {
                     throw new InvalidOperationException(errorMessage);
diff --git a/TLSharp.Core/TelegramClient.cs b/TLSharp.Core/TelegramClient.cs
index 85561ad..49a78ae 100644
--- a/TLSharp.Core/TelegramClient.cs
+++ b/TLSharp.Core/TelegramClient.cs
@@ -310,4 +310,9 @@ namespace TLSharp.Core
         {
         }
     }
+
+    public class InvalidPhoneCodeException : Exception
+    {
+        internal InvalidPhoneCodeException(string msg) : base(msg) { }
+    }
 }
diff --git a/TLSharp.Tests/TLSharpTests.cs b/TLSharp.Tests/TLSharpTests.cs
index bb3284d..2e2ba0e 100644
--- a/TLSharp.Tests/TLSharpTests.cs
+++ b/TLSharp.Tests/TLSharpTests.cs
@@ -24,6 +24,8 @@ namespace TLSharp.Tests
 
         private string NumberToAuthenticate { get; set; }
 
+        private string CodeToAuthenticate { get; set; }
+
         private string NotRegisteredNumberToSignUp { get; set; }
 
         private string UserNameToSendMessage { get; set; }
@@ -72,6 +74,10 @@ namespace TLSharp.Tests
             if (string.IsNullOrEmpty(NumberToAuthenticate))
                 Debug.WriteLine("NumberToAuthenticate not configured in app.config! Some tests may fail.");
 
+            CodeToAuthenticate = ConfigurationManager.AppSettings[nameof(CodeToAuthenticate)];
+            if (string.IsNullOrEmpty(CodeToAuthenticate))
+                Debug.WriteLine("CpdeToAuthenticate not configured in app.config! Some tests may fail.");
+
             NotRegisteredNumberToSignUp = ConfigurationManager.AppSettings[nameof(NotRegisteredNumberToSignUp)];
             if (string.IsNullOrEmpty(NotRegisteredNumberToSignUp))
                 Debug.WriteLine("NotRegisteredNumberToSignUp not configured in app.config! Some tests may fail.");
@@ -101,9 +107,23 @@ namespace TLSharp.Tests
             await client.ConnectAsync();
 
             var hash = await client.SendCodeRequestAsync(NumberToAuthenticate);
-            var code = "93463"; // you can change code in debugger
+            var code = CodeToAuthenticate; // you can change code in debugger too
 
-            var user = await client.MakeAuthAsync(NumberToAuthenticate, hash, code);
+            if (String.IsNullOrWhiteSpace(code))
+            {
+                throw new Exception("CodeToAuthenticate is empty in the app.config file, fill it with the code you just got now by SMS/Telegram");
+            }
+
+            TLUser user = null;
+            try
+            {
+                user = await client.MakeAuthAsync(NumberToAuthenticate, hash, code);
+            }
+            catch (InvalidPhoneCodeException ex)
+            {
+                throw new Exception("CodeToAuthenticate is wrong in the app.config file, fill it with the code you just got now by SMS/Telegram",
+                                    ex);
+            }
 
             Assert.IsNotNull(user);
             Assert.IsTrue(client.IsUserAuthorized());
diff --git a/TLSharp.Tests/app.config b/TLSharp.Tests/app.config
index 6fc79b3..941fdda 100644
--- a/TLSharp.Tests/app.config
+++ b/TLSharp.Tests/app.config
@@ -4,6 +4,7 @@
     <add key="ApiHash" value="" />
     <add key="ApiId" value="" />
     <add key="NumberToAuthenticate" value="" />
+    <add key="CodeToAuthenticate" value="" />
     <add key="NotRegisteredNumberToSignUp" value=""/>
     <add key="NumberToSendMessage" value=""/>
     <add key="UserNameToSendMessage" value=""/>