Can't match a CC payment as I usually do, I resolved difference adding merchant fees, but shows Unexpected Failure error message.

Welcome back to the QuickBooks Community, linda177. I appreciate you for sharing detailed information about your concern. With this, I'll be providing troubleshooting steps to ensure you can save the resolved difference entries smoothly.

A cache full of history and temp files can lead to unexpected results. Such as receiving an error message while saving an entry from a resolved difference. I recommend utilizing a private browser to access your QBO account (incognito). This ensures that the cache is the source of the problem and prevents it from keeping your browsing data.

Use these keyboard shortcuts based on the browser you're using:

• For Firefox or Microsoft Edge, press Ctrl + Shift + P.
• For Chrome, press Ctrl + Shift + N.
• For Safari, hold down Command + Shift + N.

If it works in incognito, you'll have to clear the cache of your regular browser. This deletes the history or log of sites so you can start with a clean slate. If the steps above didn't work, use another supported browser as an alternative.

Lastly, you may refer to this article to view steps on how you can reconcile your accounts to avoid any discrepancies: Reconcile an account in QuickBooks Online.

Don't hesitate to click the Reply button below if you have any other concerns or questions about matching transactions in QBO. I’m here to answer them for you and make sure you’re taken care of. Have a good one, linda177.