I am trying to sign an email with my dsc token. Token contains Digital Signature, Non-Repudiation and E-mail Protection, Document Signing, 1.2.840.113583.1.1.5, Smartcard Login, Client Authentication key usages. Encryption is not required. Only want to sign. Able to see the the certificate in both account setting and thunderbird settings. But still when I select sign and try to send a mail, not prompting for PIN and failing with " Sending of the message failed. You specified that this message should be digitally signed, but the application either failed to find the signing certificate specified in your Mail & Newsgroup Account Settings, or the certificate has expired." error message