Answer
When you click Submit on the Single Touch Payroll Preview screen in the online (web or mobile) app and receive an authentication error, the most common cause is that your account's SSID has not been registered with the ATO.
How Online STP Authentication Works
The online app does not use a machine credential (M2M keystore file) on your computer. Instead, the ATO identifies your account through a unique Software ID (SSID) that is linked to Lightning Payroll's cloud credential on the ATO's systems. Until that link is in place, the ATO will reject STP submissions with an authentication error.
Finding Your SSID
Your SSID is displayed in the top navigation bar of the web or mobile app, directly below your company name. It appears as SSID: [10-digit number]. Note it down ÔÇö you will need it for the next step.

Registering Your SSID With the ATO
You only need to do this once per account. Choose one of the following methods:
- Self-service via ATO Access Manager: Log in to the ATO Access Manager and follow the steps under Notify us of your hosted services. When prompted, enter your SSID and Lightning Payroll's ABN: 41 133 738 682 (Intellitron Pty Ltd t/a Lightning Payroll).
- By phone: Call the ATO on 1300 852 232 and provide your SSID. They will complete the registration for you.
Once the SSID is registered, return to the STP wizard and click Submit again. If the error persists after confirming the SSID is registered, contact Lightning Payroll support.
Other Possible Causes
- ABN issues: If your company's ABN is inactive or your business has been deregistered with the ATO, submissions will be rejected.
- Internet connectivity: A disrupted connection during the submission attempt can cause the request to fail with an authentication-style error. Try again once your connection is stable.
If you are using the desktop app instead and see an authentication error, the cause is different ÔÇö the desktop app uses a machine credential (M2M keystore). See Why Do I Get the STP Error Saying Failed to Collect an STP Authentication Token? for desktop troubleshooting steps.
For a full walkthrough of sending STP from the online app, see How Do I Process Single Touch Payroll?