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. 
Disclaimer:
In an effort to supply information as quickly as possible, this article has been published prior to a formal technical review, and is subject to factual, grammatical, and various structural errors. Data may be incomplete, disordered, or incorrect.
This additional disclaimer will be removed upon formal review of this article. The standard Punchh Inc. KB Disclaimer still applies, and can be found at: https://support.punchh.com/hc/en-us/articles/360040100273-Punchh-Inc-Knowledge-Base-Disclaimer