Hi Infra team， 我最近一段时间从SUSE邮箱往openEuler邮件列表发送邮件时，基本都会出现如下错误。 看起来是从我们的邮件服务器（MS Office365云）到openEuler的邮件服务器连接超时。但是经常过几个小时后，邮件又正常出现在邮件列表里面了，看起来经过很长时间之后重试又成功了。但是因此造成邮件的延迟非常高。 请帮忙排查下，谢谢！ Regards, Kai Liu 刘恺 E-mail: kai.liu@suse.com | Mobile #: +86 186 6591 9086 | TZ: UTC+8 From: post master <postmaster@suse.com> Date: Tuesday, February 22, 2022 at 15:39 To: Kai Liu <kai.liu@suse.com> Subject: Your message hasn't been delivered yet [Image removed by sender. Logo] Your message hasn't been delivered yet The message you sent to kernel@openeuler.org<mailto:kernel@openeuler.org> hasn't been delivered yet due to: Recipient server unavailable or busy. We'll let you know if we can't deliver it successfully. Further Information Connection timed out (Connection timed out) [Image removed by sender.] © 2003 - 2019 Mimecast Services Limited.