Here is a small challenge:

I invited a user to login for the first time -> She tried and could not.
I resented the password -> she tried and could not.
I deleted the user form the users list and tried to create a new one -> Could
not because the user exists in box.
I deleted the user from the box and tried to create a new one -> Could not
because the user still exist.
Checked "User Information" and could see the user, checked "Manage Users" and
could not see the user.
Search the database and located the user -> Delete manual with delete query

Trying to add the user and getting "User name already exist".

What am I missing?