diff --git a/pkg/config/config.go b/pkg/config/config.go
index 61bed75..4f36945 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -70,8 +70,8 @@ var defaultConfig = map[string]interface{}{
 	envKeyDigitalstromPassword:              deprecated,
 	envKeyDigitalstromApiKey:                undefined,
 	envKeyMqttUrl:                           undefined,
-	envKeyMqttUsername:                      undefined,
-	envKeyMqttPassword:                      undefined,
+	envKeyMqttUsername:                      "",
+	envKeyMqttPassword:                      "",
 	envKeyMqttTopicPrefix:                   "digitalstrom",
 	envKeyMqttTopicFormat:                   deprecated,
 	envKeyMqttNormalizeTopicName:            true,