Apple Card and travel
I'm travelling, and my apple card transactions don't appear to be going through. They aren't being denied, I don't see holds on the transactions, they don't show up at all.
It may be issues in your travels, merchants, payment networks etc. You can try logging out of your Apple ID/iCloud and then logging back into your account. This will remove your credit and debit cards from your Wallet and they’ll need to be added again.
Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support