Many subscribers have more than one email address. Yours seems to be logged in with the wrong one.
As owner, you could open her user record and confirm this (Admin>Members and click on the appropriate user name).
Once you figure out which address is subscribed, send that to her, and tell her to log in again with that address (see
/static/help#password). I suspect that will fix the problem.
Hope this helps,
Bruce
--
The system Help is your friend.??
/static/help