Why the sync error occurs
This error occurs when an invoice is trying to sync to QuickBooks Online from Bill.com, but a product or service on the invoice has been deleted in QuickBooks Online.
How to fix the sync error
Check QuickBooks Online for all the products and services listed on the invoice and make sure they're active. If you're not able to find a deleted item, the link between QuickBooks Online and Bill.com may be broken. Please contact Customer Support to relink the item.