Information
This setting controls whether Outlook users are allowed to send e-mail messages after they see an encryption warning dialog.
The recommended state for this setting is: Enabled
If users send messages after seeing an encryption error, it is likely that recipients will not be able to read the e-mail message.
Solution
To establish the recommended state via configuration profiles, set the following Settings Catalog path to Enabled :
Microsoft Outlook 2016\Security\Cryptography\Do not provide Continue option on Encryption warning dialog boxes
Impact:
Enabling this setting can cause disruptions if Outlook users attempt to send messages with encryption errors, although the errors themselves would likely cause disruptions in most cases if the messages were allowed to be sent.