How can this happen?
This error could occur due to API outage of your Accounting Package. You can view the API status from this links:
Xero - https://status.developer.xero.com/
QBO - https://status.developer.intuit.com/
- Click "Fix" from the Unprocessed Payments warning
- Find the Transaction
- Select "Retry"
If you accidentally clicked "Fixed Manually" instead of "Retry", you can take a manual payment to the Wise-Pay clearing account in Xero/QBO. If you take a manual payment, it is the same action that would have happened in your Accounting Package that would cause you to mark it "Fixed Manually".