diff --git a/ixwebsocket/IXSocketServer.cpp b/ixwebsocket/IXSocketServer.cpp
index 79d8d3d3..31da31c2 100644
--- a/ixwebsocket/IXSocketServer.cpp
+++ b/ixwebsocket/IXSocketServer.cpp
@@ -281,7 +281,7 @@ namespace ix
             if (_stop) return;
 
             // Launch the handleConnection work asynchronously in its own thread.
-            std::lock_guard<std::mutex> lock(_conditionVariableMutex);
+            std::lock_guard<std::mutex> lock(_connectionsThreadsMutex);
             _connectionsThreads.push_back(std::make_pair(
                     connectionState,
                     std::thread(&SocketServer::handleConnection,