Forwarding or replying to a signed message in Outlook Express causes Outlook Express to automatically attempt to sign the message
Topic Last Modified: 2005-05-19
By default, when a user replies or forwards a signed message when using Outlook Express, Outlook Express enables digital signing for that message. If the user then attempts to send the message and does not have a valid signing certificate, Outlook Express displays the following error message and does not send the message:
You do not have a digital ID.
To resolve this issue, disable digital signing for that message For more information, see Microsoft Knowledge Base article 816830, "You Receive an Error Message When You Try to Forward or to Reply to a Digitally Signed E-Mail Message."