You can see which contacts received the gift and which ones didn’t by reviewing the details of a gift campaign.

• Inside your account, click on “My Gift Campaigns”
• Choose the gift you’d like to review. 
• Click on the “Recipients” tab and click on the “Email Delivered” or “SMS Delivered” headers to sort - if you do not see a date/time stamp in the column, it means the contact’s gift was not delivered.

You can also see ongoing delivery issues by clicking on "My Contacts" and then choosing the "Delivery Issues" tab - it will list contacts with delivery failures and a reason for that failure.