When adding a new user to the blog I get the 'Invitation not sent, the user has blocked invite emails.' display occur. However, the user in question has logged in and ensured the option to block email invites is not ticked via http://wordpress.com/#!/read/subsettings/
Searched the forum but don't appear to have any consisten answer to this issue.
Blog url: http://lseitnews.wordpress.com/