Are you looking to see if any guests on your guest list have bounced back or are undelivered? When you first send out your invitation and go to the "Manage Invitation" page, you will see that the guests are in "Sending" status. After a few minutes, you will see your guests in either of these two statuses:
"Undelivered" means that there was a problem delivering the email, and it bounced back to us. You can edit by clicking on the pencil icon next to the guest's name.
"Not Viewed" means that it is has been successfully sent, and the guest has not viewed the invitation yet. You may use the "Send Message" function, to resend the invitation to specific guests of your choice.