diff --git a/src/mqtt_client_wrapper.cpp b/src/mqtt_client_wrapper.cpp
index 9bbf776..f4baddd 100644
--- a/src/mqtt_client_wrapper.cpp
+++ b/src/mqtt_client_wrapper.cpp
@@ -22,7 +22,7 @@ static void send_heartbeat()
 
     {
         std::lock_guard<std::mutex> lock(g_dispatch_id_mutex);
-        hb["dispatchId"] = g_streaming ? g_dispatch_id : "";
+        hb_data["dispatchId"] = g_streaming ? g_dispatch_id : "";
     }
 
     nlohmann::json msg;