S/MIME Signature Encryption Issue

Cannot Encrypt with S/MIME

The following error may occur when attempting to send encrypted emails from Outlook:

"A custom mail flow rule created by an admin at utdallas.edu has blocked your message. Cannot encrypt with SMIME Signature. Please remove SMIME Signature."

This error will be presented if you sign an email destined for an external recipient (outside UTD) with a digital certificate and attempt to encrypt the email with the "[encrypt]" phrase in the subject line. The encryption will fail and the message will not be delivered since the recipient is external to UTD.

You must remove the S/MIME digital signature from your email before sending it to an external recipient with the "[encrypt]" tag. For more information on sending encrypted emails, please visit KA 64.

For further assistance, please visit the Email Encryption service page or contact the OIT Helpdesk.

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Article ID: 455
Mon 11/22/21 12:56 PM
Mon 3/11/24 3:51 PM

Related Services / Offerings (1)

Email Encryption allows users to send encrypted emails to people inside or outside the organization. To view encrypted messages, recipients will receive a one-time passcode (guests), or UTD students, staff, and faculty can log in with their UTD credentials.