In Microsoft Exchange Server 2019 or Exchange Server 2016, consider the following scenario:
- User A sends an email message to User B.
- User B composes a reply by adding a S/MIME (Secure/Multipurpose Internet Mail Extensions) signature.
- User B saves the reply as a draft.
In this scenario, you find that the draft of the reply does not have a value for the InReplyTo property.
To fix this issue, install one of the following updates:
For Exchange Server 2019, install the Cumulative Update 3 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.