I have an admin for a site within our multisite install who is trying to add new users to his site. While he's able to add them, they are having problems receiving the confirmation email. We have narrowed this down to most likely being an email issue, not necessarily a WP issue, because some users are getting the confirmation email if it is sent to a different domain. But when they click the link in the email, it goes to a 404 page:
This domain is mapped into the multisite install. They user is asking for Super Admin privileges to bypass these issues (since a confirmation email is not needed if a Super Admin adds the user) but that's just not possible. I can only assume this is a relatively easy fix, I just haven't been able to find the solution doing a search for it. Thoughts?