Card blocked, but only at one place

I use my Nedbank card regularly at KFC. On Tuesday morning I wanted to pay at KFC for my order with my card and it was declined with the error message saying that my card was blocked.

Later the day I went to the Capitec branch and they checked it but couldn't find any problems. So they reset my card and pin for in case. I was told to try again. I went to Checkers and jsed the card without any problems whatsoever. This morning I went to KFC again and again my transaction was declined, again showing "card blocked". I did use the card at other places after this and everywhere it is working as normal.

What would be the problem that it only shows "card blocked" at KFC?