QuickBooks Online sync error: Duplicate Document Number Error : You must specify a different number. This number has already been used

Why the sync error occurs

This error occurs for one of two reasons:

  • When the reference number (Ref#) on a Bill.com offline payment is already in use within QuickBooks Online or has been entered on a payment that is for more than one invoice.


  • The next consecutive journal entry number is a duplicate and a funds transfer is trying to sync and use that next number.

How to fix the sync error

If the error is on an offline payment

Void the offline payment and record a new offline payment with the correct reference number.

  1. Select the Payment confirmation number from the sync status page
  2. Select Void payment
  3. Select Yes to confirm

Record a new offline payment for the bill(s).

Alternatively, record the payment manually in QuickBooks Online and contact Customer Support to request the sync error be cleared.

If the error is on a funds transfer

Bill.com uses the next consecutive journal entry number based on what was last used in QuickBooks Online, when syncing funds transfers.

To fix the sync error, change the most recent journal entry reference number in QuickBooks Online to a number that's unique, and would make the next sequential number unique.

Alternatively, you can change your QuickBooks Online preferences to allow use of duplicate journal entry reference numbers:

In QuickBooks Online:

  1. Select Settings
  2. Select Account
  3. Select Settings
  4. Select Advanced
  5. Set Warn if duplicate journal number is used to No

Save and sync again.