An order in Shopify can fail to export to QuickBooks Online for a variety of reasons. If you navigate to Shopify admin -> Apps -> Intuit QuickBooks Online, and select the export date with errors, you'll be able to review the list of orders that failed to export and an explanation for each.
If you need clarification on the reason for the failure or aren't quite sure how to resolve it, please contact our Merchant Success team for help.
