Hi Amanda

It is possible for users to disable email in their profile so they wouldn't be sent emails.

If the email is an alert or a task it is also possible to turn off the receipt of these by email in the users profile.

The other problem could be the email could be being blocked by the email client by the server or by a rule on the users email client.

Can you check if these conditions apply - if not then you may need to look at some logs and see if they have been sent from the server.

regards

Craig