QuickBooks Online Sync Error | Invalid Reference IDs {element_type} {element_id}

If the customer is active, try these steps to resolve the sync issue:

1. Go to Accounting → Ready to Sync.
2. Mark the affected items as Not Ready so you can edit the transactions.
3. In the QuickBooks Customer field, select an option from the dropdown, even if it is the same customer.
4. Mark the items as Ready for Sync again and retry the sync.