Hi books2019, 

Thanks for reaching out. The first thing I'd recommend checking is that the Payment File settings are all correct. 

1. Navigate to the Employee section > Payroll Settings 

2. Select Payment Files under Business Settings 

3. Under ABA File Settings select your Account Name 

4. Ensure there is an APCA User Id entered

5. With NAB you will need to tick Include Self Balancing Transactions 

6. Save 

If Include Self Balancing Transactions was not ticked please download a new ABA file and attempt the upload again. 
If all of these settings are correct I would recommend contacting NAB for further information.

 For more information about Payroll ABA Files please refer to this article: https://support.yourpayroll.com.au/hc/en-au/articles/200123570-ABA-Files

Please don't hesitate to reach out if you have any other questions. 

Rebecca