diff --git a/TelegramBotBase/Base/MessageClient.cs b/TelegramBotBase/Base/MessageClient.cs
index 5d82f8d..3999bdd 100644
--- a/TelegramBotBase/Base/MessageClient.cs
+++ b/TelegramBotBase/Base/MessageClient.cs
@@ -111,7 +111,7 @@ public class MessageClient
 
     public virtual void StopReceiving()
     {
-        _cancellationTokenSource.Cancel();
+        _cancellationTokenSource?.Cancel();
     }
 
 
diff --git a/TelegramBotBase/Base/ThreadPoolMessageClient.cs b/TelegramBotBase/Base/ThreadPoolMessageClient.cs
index 41fb131..c70fc9d 100644
--- a/TelegramBotBase/Base/ThreadPoolMessageClient.cs
+++ b/TelegramBotBase/Base/ThreadPoolMessageClient.cs
@@ -81,7 +81,7 @@ public class ThreadPoolMessageClient : MessageClient
 
     public override void StopReceiving()
     {
-        _cancellationTokenSource.Cancel();
+        _cancellationTokenSource?.Cancel();
     }