Uploading your invoices to QuickBooks lets you track and manage these data in the program, Samuel. I'm here to lend a hand so you can get past the error you've encountered and provide more details about it.

This error occurs when you're trying to access some QuickBooks feature that is beyond your user access. That said, please review this link and check if your user role limits your allowed actions within your company's invoice data: User roles and access rights in QuickBooks Online.

Nevertheless, if you have access rights to import invoices, let's troubleshoot your browser. There must be an overwhelming volume of browser data, which slows down the system's performance. When this happens, QuickBooks will tend to showcase abnormality in its functions.

Given that, let's open your account using a private browser to isolate this matter. Please follow these keyboard shortcut keys to proceed:

• Safari: Command + Option + P
• Google Chrome and Microsoft Edge: CTRL + Shift + N
• Mozilla Firefox or Internet Explorer: Shift + CTRL + P

If you can seamlessly import your invoices using private windows, it confirms a problem with your regular browser. Let's fix this issue by clearing its cache and cookies.

However, if the issue continues after following every procedure, I recommend using another supported browser to narrow down the result. 

I'm also adding this article that provides complete information about importing numerous invoices in one go: Import multiple invoices at once in QuickBooks Online.

Finally, once your customer pays their outstanding invoice, you can enter an invoice payment to clear off its balance. It completes the sales transaction and ensures accurate data in your books.

Let me know if you have more concerns with uploading your invoices or any transactions in QuickBooks by replying to this thread. I'm always happy to assist.