A recent change to the Xero UI has resulted in a breaking change, where when an existing item description is > 1000 characters.
The issue is that the sales or purchase description is greater than the allowed limit in the new Xero UI interface. When the invoice is being created, the API throws an error as the description is too long and cannot be updated.
Please refer to the Item Noted in the Batch Results (from Wise-Sync).
In Xero, click on "General Settings > Inventory Items"
Search for the item from the error:
You will notice when you attempt to edit the desctiption, you will be prompted with the warning:
Item Description Error: Description is greater than the allowed length.
This cannot be resolved without deleting the item.
From the list of Items, select the item and press the delete button.
This will delete the item from Xero Inventory Items, and the item will be re-created with the same details (this time with a reduced detailed description).
You will now be able to sync the Invoice normally.