Why Is Cloud Giving Me a Duplicate Credit Card Error?

The majority of the time you're probably not entering an actual duplicate credit card into Cloud. The alert comes up when two cards share the same last four digits, or have another similarity, but aren't necessarily identical. You can use the Credit Cards--All report to double-check that the card you're entering isn't a duplicate. However, if that report shows two cards having the same card type, last four digits and expiration date, chances are the cards are actually identical. Otherwise the alert is something you can double-check and then click through. You might receive this error more frequently with Amex cards, because oftentimes they have the same last four digits.

After confirming the two cards are not genuine duplicates, the alert is something you can click through.