Error 6140 occurs when the document number you are attempting to use has already been assigned to a prior transaction, Ohgreatone01. I'll share some details to assist you and clarify how transaction numbers are managed in QuickBooks Online.
Could you first specify which third-party application is integrated with your QuickBooks Online account? Are you a developer?
Please keep in mind that QuickBooks Online will continue with the next number in the sequence, including any prefixes or additional characters, when generating sales transactions. This is why the next invoice is automatically assigned App_1001, as App_1000 is already recorded in QBO.
For now, there's no option to create a separate sequence for invoices synced from different sources compared to those created directly in QuickBooks Online.
However, you can manually override the transaction number when creating invoices in QBO to avoid using the prefixes from the third-party app.
If you're a developer, we provide a dedicated Community and support site specifically for Intuit Developers like you. On this site, you can find resources and submit questions related to developing and synchronizing applications with QuickBooks Online.
Follow these steps to access the site and how to post your inquiries:
- Go to this link: https://help.developer.intuit.com/s/.
- Choose your QuickBooks product relevant to your integration.
- Click on "Ask a Question".
- Sign in and follow the prompts appearing on the screen to continue.
Allow me to share these articles for further guidance on managing third-party integrations in QBO:
Please feel free to reach out to us anytime you have further questions regarding data synchronization, invoice management, or general bookkeeping tasks in QuickBooks Online. We're always here to assist you.
