Occasionally a card may not seat itself fully and cock the springs back quite all the way, so that the springs cannot push the card out when you request an ejection. Try pushing first on one corner of the card, making sure its firmly seated, then try the ejection again. If that does not work, push the other corner of the card and try the ejection.

If the card still does not auto-eject, you'll have to manually eject the card by inserting a bent paper clip into the hole next to the card. Notice that the upper and lower slots each have their own ejection hole.