When setting up your QuickBooks integration, you can choose whether Productive or QuickBooks generates invoice numbers.
If you select QuickBooks, invoices may fail to send if the Custom transaction numbers option is enabled in your QuickBooks account.
Why this happens
1. QuickBooks as the number generator
When Productive is set to let QuickBooks assign invoice numbers, Productive does not provide a number itself. It expects QuickBooks to handle that automatically.
2. Custom transaction numbers enabled
If the Custom transaction numbers toggle is on in QuickBooks, it expects a number to be supplied manually. QuickBooks won’t automatically assign the next sequential number.
3. Conflict during invoice copy
When Productive sends an invoice without a number (because it expects QuickBooks to generate it), QuickBooks refuses to accept it. This causes the invoice to fail and not appear in QuickBooks.
Solution
Disabling Custom transaction numbers tells QuickBooks to automatically generate the invoice number. After that, Productive can send invoices successfully, and QuickBooks assigns the correct sequential number.
How to Disable Custom Transaction Numbers in QuickBooks
In QuickBooks, click the ⚙️ Gear icon (Settings) in the top-right corner.
Select Account and settings.
From the left-hand menu, choose Sales.
In the Sales form content section, click anywhere inside the section to expand it.
Turn off the toggle for Custom transaction numbers.
Click Save, then Done.
After disabling this option, invoices sent from Productive with QuickBooks as the invoice number generator will copy successfully.