The most common reason an e-card is not successfully delivered is an incorrectly entered email address. Yahoo! Kids E-cards does not know if the email address you have entered is valid so it's up to you to be sure to enter the recipient's email address correctly.
If the recipient didn't receive the card, you could try sending the card again making sure to carefully enter the correct email address. If this still doesn't work, contact the postmaster of the recipient's email domain to see if they are experiencing any delays.
Since our cards are sent directly from Yahoo! Kids E-cards, they won't show up in your outbox, and you won't receive an undeliverable address message in your account for mistyped addresses.