I added a resolving transaction but it doesn't allow me to save?

Hi Robbie,  

QuickBooks Online provides the ability to record transactions with associated bank fees, so you can balance your books with peace of mind. I'd be glad to show you how! 

If you already have an expense account for bank fees, you can resolve the difference between the invoice and the payment when matching transactions from your bank feed:
 

1. Go to "Transactions", then select "Bank transactions"
2. Select the blue tile for the bank account with the transaction
3. Open the "For review" tab, locate and select the transaction
4. Select "Find match"
5. In the Match transactions window, checkmark the box for the appropriate Invoice
6. Click on "Resolve" to open Add resolving transactions
7. From the Category dropdown, select the Bank fees expense account you created
8. Enter the Amount of the bank fee
9. Select the applicable sales tax
10. Hit Save.

Your transaction is now matched, and the bank fees are accounted for. Here's a guide for reference.

If you have any other questions, feel free to reach back out here.