Please verify that the conferees' e-mail addresses were correctly typed.  You may wish to review the entries in your address book.  Our system makes its best attempt to deliver the invitations and will notify you if any of them “bounce” back to us.

We also suggest that invitees check their spam or other organizational folder first. In gmail for example, they sometimes land in the promotions or update folders.

If they don’t find it there, then I recommend adding the following email address to their list of contacts. This will mark your email invitations as being sent from a known sender and prevent them from being deleted or blocked in any way.

You can also re-send invites via the 'Manage' page of your account.