Perhaps some misunderstanding exists between 'Apple Pay' with banks involved
and then, Apple Card; which has Goldman Sachs sponsorship? Might this Wallet
have some different cards attached to its function, from another regional bank?
I've kept online banking simple as possible; few cards ~none get used automatically.
The rules for Apple Card are quite different than Apple Pay. Are you located in USA?
If a payment card that you use with Apple Pay is declined - Apple Support
Update your Apple Card account information - Apple Support
First up would be lack of Apple Card/Goldman Sachs ability to function outside US.
..Check the settings in your device, and see where they might be seen as incorrect.
These user-to-user communities help is not official Apple Support, while they may be
contacted through these Community pages. Two locations per page, upper-right and
lower-left side; links say Support. They may have workable solutions to resolve issues.
