FAQ 000163 – SMTP Error 451 5.7.3 Cannot achieve Exchange Server authentication

This article applies to: Exchange 2010, Exchange 2016, SMTP In this article I will show an example of Exchange 2010 to Exchange 2016 mail flow trobleshooting, based on a recent customer support case. PROBLEM The customer is in a process of migrating from Exchange 2010 to Exchange 2016. The environment consists of 2 Exchange