There may be cases where users have emailed their receipts and expecting to see them in their Files & Receipts.
For cases where they are missing administrators have a new tool to help them identify why they are missing.
You can find this tool by going to Administration > General > Orphaned Emails.
Most common reasons are a misspelling in the recipient email address or the user using their personal email address.
For cases where a user has used another email address which has not be added to the email allow list. You will be able to add the email to allow list which will also forward the orphaned email receipts to the user.