Hard the same thing happen to me just now, semi-panicked and was stupid enough to call the Goldman Sachs Apple Card number. Got shunted to interminable muzak when I opted for a live human being. Then the lightbulb went on over my head, and I checked Apple System Status, and lo and behold saw a more helpful message, which read,
"Apple Card - Issue
"Yesterday, 8:00 AM - ongoing
"Some users are affected
"Some users may see a message in their Wallet that Apple Card can not be used. Please follow the instructions to remove your Apple Card, re-add it to the Wallet by tapping the (+) Add button, tap Previous Cards, and follow the steps on the screen. Your transaction history will reappear after re-adding your Apple Card."
It works.
Do you suppose someone in the Goldman Sachs IT department just tried turning it off and on again?