Apple Pay keeps declining purchases

Within the past week or so, as I try to use Apple Pay, my charges are being declined. Within Settings, the security Code is not saved. I have added the security code back and saved. The next time I went to use Apple Pay, my purchase was declined. Looking back in Settings, security code is blank. I have removed and re-added the card, but get the same results. I have an iPhone 11 Pro Max using IOS 15.5. I rely on Apple Pay and want to get this resolved. Any ideas?