Hey there, @hhoa.
Thanks for reaching out to us in the Community. Allow me to chime in and help make sure that the outstanding balance will show on the account summary when printing invoices in QuickBooks Online (QBO).
Since you already enabled the account summary feature, let's perform some troubleshooting steps that can help us isolate this. To start off, try logging into your QBO using a different or a private browser. There are times that the browser is full of frequently accessed page resources, thus causing some errors and/or unusual responses.
To use a private browser, here's how:
- On your keyboard, press Ctrl + Shift + N (Google Chrome).
- Ctrl + Shift + P (Firefox or Internet Explorer).
- Control + Option + P (Safari).
Once logged in, try to reprint that specific invoice to double-check. If it works, return to your default browser and perform clear cache to remove temporary internet files on your computer. Before doing so, make sure to take note of your saved passwords and URLs.
For future reference, you can also check out this article for more information: Account Summary on an invoice.
That should get you fixed right up. Please let me know how it goes by leaving a comment below. I'll be here if you need further assistance. Take care and have a good one!