Using OWA I cannot send a message that is digitally signed. I receive the error: This message can't be sent right now. Please try again later. I have the S/MIME controls installed. When I view the S/MIME settings in OWA there is no default certificate for digital signing. When I click the Choose a certificate button a message appears: No certificate was found. If you have a smart card-based certificate, insert the card and try again. The card is inserted and I can utilize the certificates to access other websites.