This is to check if the error is caused by the browser. Start with a private window:
Google Chrome: press Ctrl + Shift + N
Mozilla Firefox: press Ctrl + Shift + P
Internet Explorer: press Ctrl + Shift + P
Safari: press Command + Shift + N
If you're able to cancel successfully via the private window, go back to the main browser and clear its cache to start with a clean slate. You can also use a different browser.
If the error persists, I recommend contacting our QuickBooks support so they can check your account: