If you recipient has not received the email notification, it has ended up in their spam/junk folder. We have taken precautions so that emails will not be caught in such filters, but it can happen in some cases. Tell your recipient to have a look in the spam/junk folder, and to add our notification system email address (This email address is being protected from spambots. You need JavaScript enabled to view it.) to their contacts address book. After they add the contact, they will not have any problems receiving files from you again.