Error: Duplicate Document Number Error

Occurs: When import a transaction into QuickBooks Online the import fails with the error message "Duplicate Document Number Error : You must specify a different number..." and the import for that transaction fails
Cause: QuickBooks Online is set to not permit duplicate document numbers when you try to import a transaction with a DocNumber that has previously been used, QuickBooks rejects the transaction.
Resolution: There are a couple of ways to resolve this error
  1. You can change your settings in your QuickBooks Company File to permit duplicate document numbers by selecting the option in the QuickBooks Online > Account and Settings area to use Custom transaction numbers 
  2. You can select the option in Zed Axis to use Auto Numbering
  3. You can modify your transactions number you are importing to avoid the duplication