A coworker is having trouble sending e-mails with Outlook Express.

Basically, she forwards other e-mails as attachments of a new e-mail. But when connecting to the server and trying to send it, qmail (used by the host) rejects it right away, giving the error message "451 See http://pobox.com/~djb/docs/smtplf.html".

Apparently this has something to do with the way e-mails are formatted? Has anyone encountered this problem in OE before? If so, how did you fix it?

Thanks in advance,
- Bernard