Failure to match receipts with transactions

It's my pleasure to assist you today, bc1-red-gp.

QuickBooks Online (QBO) reads the receipts, extracts information, and automatically matches to a transaction. What hinders it from matching can be cause by the following reasons:

• The transaction has been previously matched to another transaction.
• The information didn't match. (e.g. recorded in a different bank account).
• The transaction is not in the books.
• The transaction is older than 180 days.

You can read more of these articles about matching and managing receipts: 

• Capture and categorize receipts and bills.
• Manage your receipts in the Receipts tab

With regards to your concern about how to change receipt matching rules to make them more flexible, QuickBooks only recognize and apply the specific rules you've set. What you can do is to match your receipts with QBO transactions manually. 

Learn more about managing bank rules through this article: Setup bank rules to categorise online banking transactions in QuickBooks Online.

Also, here's an article you can read to for the steps on how to matching and manage your downloaded transactions and uploaded receipts: Download, match, and categorize your bank transactions in QuickBooks Online.

Come and visit us again if you need help. It will be my pleasure. Stay safe and have a great day ahead!