QuickBooks Online Sync Error: Reference/Check number for this payment is already being used in QBO. The payment may already be recorded in QBO.

Why the Sync Error occurs

This error occurs when a manual payment has a reference number (Ref#) that is already in use in QuickBooks or a manual payment has a Ref# when it is for multiple invoice payments.

How to Fix the Sync Error

There are two options to resolve this issue:

  • If the issue is due to a single invoice, edit the payment to update the Ref# to a unique number ~ or ~
  • If the issue is due to multiple invoices, edit the payment to remove the Ref#