Can anyone help with addressing an error code on payroll submission to HMRC?

The error message that you received indicates that your login credentials are incorrect, Eddie.

You might be using the wrong Government Gateway login information, so it is essential to ensure you have the correct details specific to payroll. If you copy and paste your username and password, try typing them in manually instead.

On top of that, double-check that you've entered the correct PAYE reference number. If you've just activated your account, keep in mind that it may take some time for HMRC to verify it and update their system.

Please check out this article to know more about payroll error codes: Fix payroll error codes in QuickBooks.

You can also explore this article to guide you through the process of creating, customising, and managing your payroll reports: Create and customise your payroll reports in QuickBooks Online.

We will keep this thread open if you have additional questions or concerns. Feel free to click the reply button, and we're here to help.

Disclaimer: I have updated my response about the payroll error code.