Error: "IRD response code: 4..." when filing a GST return (New Zealand)

This error can occur in MYOB Exo Business when filing an NZ GST return. It stops the IR login authentication window from opening.

The error is caused by an incorrect value for the user in the staff table. To fix it, update the SBR_Session_ID field in your database's staff table to null, or contact your Exo Business support partner.