Declined payment (Amex)

I had a notification that a transaction got declined today for a transaction that may have failed as it was fully processed on the same day Curve and Amex ended.(29/01/19). I noticed there is a Curve top up pending on my Amex account on same day. After I heard the news on Monday I had emptied my Amex wallet. Is it possible that the shop I used was slow at processing payment and then couldn’t due to the Amex wallet not being able to top-up?

Not sure how that would work out. The shop is charging Curve, it has no relationship to anything beyond that

Yes it looks like the shop pre authorised the card but did not take payment so it became declined on the app. But they can payment again at least.