这个域名是在ubuntu18上安装了ubunutu10的https://my.freenom.com/上创建的 当我使用我的yahoo.com帐户发送电子邮件时(我在该帐户下进入主仪表板),我收到了电子邮件message \"421 Domain my-demo-apps.tk is not allowed to send: The domain is unverified and requires DNSLog in to your control panel to view required DNS</em