There are a few different reasons why you might not be able to use a support card.
The message above the second support card is saying that you can’t use it while training that uma. Since the uma being trained is King Halo, I cannot use King Halo’s support cards.
The message above the third support card is saying that another support card of the same uma is present. The deck already contains the Speed version of Special Week, so I can’t add the Guts version of Special Week.
The message above the first support card is simply saying that the card is already present in the deck.