Cannot add Gift Card Codes

So add me to the list of users who cannot add their gift cards to their wallet.
But this isn't the usual case of buying the cards at a store... it's Samsung Pay!
I have done this before at least thrice, and it has always worked.
Now, I got [redacted amount of cards and values of each], as there is a 4x Samsung Rewards point promo currently going on. Taking it to my advantage, I figured to buy them, and try to snag a couple of the fall games. But NOOOOOO, Sony saying, on the PS4 AND browser, that the codes aren't working.
Question though: Is there a hard cap on how much you can add in a given month? No, not the $150 or whatever it is cap on the wallet at once... I mean like spending limits?

EDIT: Grammar.