Added a debug print

main.go

@@ -38,7 +38,8 @@ func main() {
 	e.HideBanner = true
 	e.Use(middleware.BodyLimit("1M"))
 
-	os.Mkdir(SERVER_PATH, os.ModePerm)
+	a := os.Mkdir(SERVER_PATH, os.ModePerm)
+	fmt.Println(a)
 	os.Mkdir(SERVER_PATH + "images", os.ModePerm)
 
 	e.GET("/list", listFiles)