Hello there, @ozdavis. Let's figure out why transactions are unable to find their match in QuickBooks Online (QBO).

By default, QBO tries to find a match between the transaction's Date, Description, Payee, and Amount with the existing records. However, it sometimes fails to detect a match from the existing records due to the following reasons:

• The payees, amounts, or dates don’t match.
• The transaction is older than 6 months.
• The bank account used for payment is different from the bank where the match is located.
• The payment has been reconciled.
• The record is already matched to another transaction. 
• There are multiple currencies involved, and the exchange rate has changed significantly, causing large differences in amounts.

That said, I recommend reviewing the transaction details to ensure they match. Alternatively, you can utilize the Find Match feature to assess the list of possible matches. You can read this article for more information: Find and categorise transactions in QuickBooks.

Additionally, you can create rules for your bank transactions in QBO so they will automatically categorise into the appropriate accounts.

If you need further guidance in matching your transactions, please don't hesitate to reach out to the community for help. We are always here to assist you. Take care, and have a wonderful day!