Business Validation Error: There is no account associated with the item.
In this case, it is likely that that product already exists in QuickBooks Online. If so, you can verify that it is marked for purchase via the "Purchasing Information" checkbox on the Inventory Item Record. If that option is not yet enabled, then please enable it. Note that you will also need to specify an expense account.
1. In QuickBooks Online navigate to the Gear icon and then Products and services
2. Select the product listed in the error
3. Check "I purchase this product/service from a vendor
4. Select the Expense Account
5. Click Save and Close
6. Rebatch the invoice