I have a user who, when I try to invite him to a particular one of our defined (private, moderated) sites, his Add button is grayed out, but he doesn't appear in the pending lists for that site. He has been successfully added to one other site, but only to one.
Where should I be looking? Our user accounts are integrated with LDAP, and since it's worked once, I'm not suspicious of LDAP. Also, I have other users who have joined multiple sites without problems.
Thanks!