请教各位：我们的环境是两台mbx做DAG，两台CAS做前端NLB。在垃圾邮件网关上经常看到有大量的延迟的邮件发给inboundpoxy.com，发现邮件内容中都有如下信息。（域名显示已更改）
供管理员使用的诊断信息:
生成服务器: HMbx02.harX.com
接收服务器: HMBX01.harX.com (172.30.2.22)
HealthMailbox9f97dd8e518749368080981c88361b44@harX.com Remote Server at HMBX01.harX.com (172.30.2.22) returned '400 4.4.7 Message delayed' 2014/1/9 20:22:31 - Remote Server at HMBX01.harX.com (172.30.2.22) returned '451 4.4.0 Primary target IP address responded with: "454 4.7.0 Temporary authentication failure." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts. The last endpoint attempted was 172.30.2.22:475'
请问是否在我们的Exchange 2013服务器有问题了。如何进行下一步的检查和处理。