Consider the following scenario:
You send an email message by using a Microsoft Exchange Server 2016 mailbox.
The subject line of the email message contains unrecognized ChineseBig5 character set (character set value is 136) encoded characters.
In this scenario, the email message isn't delivered. Additionally, you don't receive a non-delivery report (NDR) message.
This issue occurs because the character set name (136) isn't defined as ChineseBig5 in the Exchange database. Therefore, when Exchange Server 2016 tries to decode the email message, an invalid charset exception occurs.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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