From the AWESOME blog of Mr. Cunningham
Exchange 2016 CU1 Edge Transport Recipient Validation Bug
Hi there, Exchange 2016 Cumulative Update 1 was released two weeks ago, and news has emerged of a bug impacting Edge Transport servers. In short, the bug will affect Edge Transport servers that are performing recipient validation, and may result in legitimate email being rejected. Microsoft has acknowledged the bug in their release notes for Exchange 2016 and provided steps to mitigate the issue. Read more Paul Cunningham Microsoft MVP, Office Servers and Services
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