You receive a "Microsoft Outlook could not sign or encrypt this message" error message when you send or read a signed e-mail message in Outlook 2003

When you try to send a new signed e-mail message or to encrypt a new e-mail message or to decrypt a received e-mail message in Microsoft Office Outlook 2003, you may receive the following error message:

This problem occurs when your e-mail account has been migrated to a new Microsoft Exchange server. The Key Management Services (KMS) certificates that are issued to your e-mail account will not be migrated to the new e-mail account unless they are correctly prepared for migration.

To work around this problem, your system administrator must reissue certificates for each user who was migrated to the new Exchange server.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

After your system administrator issues new KMS certificates to the user accounts on the original Exchange server, the administrator must run the GalSynchronization Management Agent (GalSync) before using the Migration Wizard to migrate the accounts from the original Exchange server to the new Exchange server. This will let the certificates that are assigned to each user account migrate correctly to the new Exchange server.