diff --git a/cmd/config.go b/cmd/config.go
index 4766c389..83e7620e 100644
--- a/cmd/config.go
+++ b/cmd/config.go
@@ -99,7 +99,7 @@ func getProxyAuth(flags *pflag.FlagSet, defaultAuther map[string]interface{}) (a
 		return nil, err
 	}
 
-	if header == "" {
+	if header == ""  && defaultAuther != nil {
 		header = defaultAuther["header"].(string)
 	}