QuickBooks Online Sync Error: Bill/Invoice number is being used on another bill from the same vendor. Use a unique invoice number for the vendor bill.

Why the Sync Error occurs

This error occurs when the bill/invoice number is already in use for that vendor or customer in QuickBooks Online (QBO). It may also occur if the bill/invoice link between PayMaker and QBO is broken when the sync error is an update.

How to Fix the Sync Error

There are two options to resolve this issue:

  • If the bill/invoice is erroring while trying to create in QBO, use an alternate bill/invoice number
  • If the bill/invoice is erroring while trying to update in QBO or if it already exists in QBO and needs to be linked to the one in PayMaker, edit the bill/invoice in QBO, save, and sync again