What It Means
The account period was closed in QuickBooks/Xero and you can no longer sync transactions into it or edit it any other way.
You are trying to sync transactions for a period that has already been reconciled and closed in your accounting company, which is not allowed by the accounting system.
How To Fix It
It is possible to re-open the period in your accounting company. Please refer to how-to guides of your accounting company to learn how it is done. However, make sure you absolutely need to sync the transactions for that period, as you should have all the data in your QuickBooks/Xero already, and syncing may cause duplicates and impact your books from that period onward.
If the issue persists, please contact our support team. We’ll do our best to solve your problem!