In a Microsoft Exchange Server 2016 environment, the Transport service may not send email messages that contain an attachment that was encoded with Unix-to-Unix Encoding (UUE) type. When this issue occurs, you experience the following exception:

554 5.6.0 Corrupt message content
Failed to process message due to a permanent exception with message. The message content has become corrupted.


This issue occurs because the UUE attachment size exceeds the defined MaximumBytes of the Transport's UUDecoder.


To resolve this issue, install Cumulative Update 5 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


Learn about the terminology that Microsoft uses to describe software updates.

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