diff --git a/code/components/jomjol_mqtt/interface_mqtt.cpp b/code/components/jomjol_mqtt/interface_mqtt.cpp
index 38381076..bb3f0078 100644
--- a/code/components/jomjol_mqtt/interface_mqtt.cpp
+++ b/code/components/jomjol_mqtt/interface_mqtt.cpp
@@ -135,8 +135,8 @@ static esp_err_t mqtt_event_handler_cb(esp_mqtt_event_handle_t event) {
         
         case MQTT_EVENT_DATA:
             LogFile.WriteToFile(ESP_LOG_DEBUG, TAG, "MQTT_EVENT_DATA");
-            LogFile.WriteToFile(ESP_LOG_DEBUG, TAG, "TOPIC=" + str(event->topic));
-            LogFile.WriteToFile(ESP_LOG_DEBUG, TAG, "DATA=" + str(event->data));
+            LogFile.WriteToFile(ESP_LOG_DEBUG, TAG, "TOPIC=" + std::str(event->topic));
+            LogFile.WriteToFile(ESP_LOG_DEBUG, TAG, "DATA=" + std::str(event->data));
             topic.assign(event->topic, event->topic_len);
             if (subscribeFunktionMap != NULL) {
                 if (subscribeFunktionMap->find(topic) != subscribeFunktionMap->end()) {