When guests are not able to earn points when scanning the barcode on a receipt, they will receive an error or checkin failure. This can happen for several reasons, including scanning too many receipts in a time period, scanning a receipt that is too old, or the POS has not sent over the matching transaction, yet.
These checkin failures have been relocated to their own section of the guest timeline, and should be checked when a guest reports an issue with earning on a receipt. 