I understand this can be concerning, especially when managing your invoices, Bjorn2.
To ensure compatibility with QuickBooks, log in using QuickBooks-supported web browsers to prevent errors, such as being unable to mark the invoice as paid.
If the issue persists, I suggest contacting our Live Support team directly. They can help you determine the root cause of the error when marking the invoice as paid. Here’s how to reach them.
- Head to the Help icon in the upper right corner of your screen.

- Select the Contact Us option.

- Enter your concerns, then hit Continue.

If you want to customize and manage your invoices, refer to this article: Create invoices in QuickBooks Self-Employed.
If you have any other questions about invoices, let us know in the comments below.