Stores are not accepting myApple card.
Recently, the two most recent retailers I've tried to use my Apple Card at have refused it. Both have previously accepted it. In both cases, the message was something like "This reader does not accept this type of card." So it's not my card specifically, it's the Apple credit card. (It seems extremely unlikely that two stores have quit accepting MasterCard, so it's either Apple, or the bank that issues the card. And FWIW I am up-to-date on my payments.)
What's going on?