I have a user I'm trying to add to our External Yammer Network, when I try to invite her I get a email message "We could not invite first.last@ab.companyname.com to Yammer because they have placed themselves on our never email list.". Other users from the same email domain can register with our network, but just not this individual. As far as I know the user has never used Yammer before, and can't register now either, as they don't receive the confirmation email. So it is a bit of a mystery as to 'where' this 'Never Email' list is and how to remove someone from it.
Any ideas?