版本 2010
只需要关闭：要求所有发件人通过身份验证
位置： Exchange 管理控制台
取消勾选，再点确定即可
参考资料： https://portal.thobson.com/knowledgebase/427/550-511-User-unknown--How-to-fix-this-email-error-in-Exchange-Postfix-and-Qmail-servers.html#:~:text=The solution is to check and verify that,recipient configuration and click on mailbox or list.
