The error message that you've received indicates that your login credentials are incorrect, Eddie.
To begin with, we recommend clearing your cache and cookies, as they can contain outdated or incorrect information that can lead to unexpected behavior, error messages, or functionality issues. You can also use up-to-date and supported browsers to ensure that you receive the latest features and enhancements.
After successfully troubleshooting, ensure that your His Majesty's Revenue & Customs (HMRC) username and password are correct by logging in to your PAYE Gateway account, then you can delete and re-enter these details manually and submit the Full Payment Submission (FPS).
You can also check out 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.
