diff --git a/telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/DefaultBotSession.java b/telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/DefaultBotSession.java
index b7d7140a..cc89f90b 100644
--- a/telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/DefaultBotSession.java
+++ b/telegrambots/src/main/java/org/telegram/telegrambots/updatesreceivers/DefaultBotSession.java
@@ -61,7 +61,7 @@ public class DefaultBotSession implements BotSession {
 
     @Override
     public void start() {
-        if (running.compareAndSet(false, true)) {
+        if (!running.compareAndSet(false, true)) {
             throw new IllegalStateException("Session already running");
         }