Hey, Anna !
Thanks for posting! :)
That's interesting, usually there shouldn't be any problem accepting payments with American Express when using Shopify Payments.
However, a good way of assessing the payment of an order would be within the order timeline at the bottom of the page. This can show you the history of each payment, and any extra info on why a this may not have been successful.
Hope this helps you out!
Koreen W | Shopify
Actually we have had a customer that claims he was having issues making a payment with his Amex card. He tried a few times and was unable to make the payment. We still don't know what the issue was. I spoke to the support team at shopify to see if it could possibly be a settings issue but they say everything is fine. It's still a mystery.
We have been having A LOT of issues with AMEX. We recently had a transaction with a low fraud analysis occur and it's still pending. Shopify posted the usual payout date and now days after that date we still don't have the funds. It's a big headache and it slows down our business. I'm not sure if this is AMEX or Shopify but we can't run our business like this.