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Technical errors – all audiences

How to resolve common errors and issues affecting all audiences when accessing ATO online services.

Last updated 30 June 2025

A system error has occurred

Possible cause and solution

Possible cause

What you can do

ATO online services outage or error

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Restart your computer.

Browser crashes, closes or page hangs

Possible cause and solution

Possible cause

What you can do

Server has timed out or internet connection issues

Clear the cache and cookies in your web browser and try again.

Restart your computer and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Check if there is an issue with your network settings by logging in from a mobile or laptop connected over cellular 4G/5G (not to an office or corporate Wi-Fi).

If you are using a business security solution, such as VPN, contact your internal IT support.

If none of the above have worked, and you are using Chrome, contact your internal IT support to create a new Chrome profile.

Site under maintenance / Under construction

Possible cause and solution

Possible cause

What you can do

Website is being updated

Check our system maintenance page for outage notifications.

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

Unexpected error / Process error / Internal error

Possible cause and solution

Possible cause

What you can do

ATO online services outage or software issue

Check our system maintenance page for outage notifications.

Clear the cache and cookies in your web browser and try again.

If you are using Firefox, make sure you enable 'Remember history'. To do this:

  • select the menu button (3 horizontal lines near top right) and select ‘Settings’
  • select the ‘Privacy and Security’ panel and go to the 'History' section
  • select the drop down and change to 'Remember history'
  • close and re-open Firefox.

Try an alternative supported web browser such as Firefox or Chrome.

Error: Function unavailable / Unknown Error

Possible cause and solution

Possible cause

What you can do

ATO online services outage or error

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Restart your computer.

Cert Validation Failed (A911.03 / A919.05 / A927.30 / A927.31 / A927.32 / A927.34)

Possible cause and solution

Possible cause

What you can do

ATO online services outage or software issue

Check our system maintenance page for outage notifications.

Clear the cache and cookies in your web browser and try again.

If you are using Firefox, make sure you enable 'Remembering history'. To do this:

  • select the menu button and select ‘Settings’
  • select the ‘Privacy and Security’ panel and go to the 'History' section
  • select the drop down and change to 'Remember history'
  • close and re-open Firefox.

Try an alternative supported web browser such as Firefox or Chrome.

Error: A918.26

Possible cause and solution

Possible cause

What you can do

Server is not connecting

Refresh the web page (Windows: ‘Ctrl + F5’ or Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

If you are a:

  • Business user, phone the ABR on 13 92 26 to verify your ABN
  • Tax agent, phone the Tax Agent line on 13 72 86 FKC 33 to verify your TAN or RAN.

(ATO Online) A system error (A927.06/ Unknown error/ unexpected error / Session error etc)

Possible cause and solution

Possible cause

What you can do

Platform issues

Check our system maintenance page for outage notifications.

Close and reopen the browser and try again.

Clear the cache and cookies in your web browser and try again.

Check your system compatibility by selecting 'Online services system requirements check'.

Try an alternative supported web browser such as Firefox or Chrome.

Try using a different device.

Try again later.

Error: Session timeout (A927.42 / A927.39)

Possible cause and solution

Possible cause

What you can do

Session timed out

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

If you are using a third-party software to generate reports, try generating reports directly through ATO online services.

Restart your computer and try again.

Error opening file for writing / autorun.inf

Possible causes and solutions

Possible cause

What you can do

Firewalls

Start the installation again and select ‘Ignore’ when the error appears.

This connection is untrusted / Your connection is not secure

Possible cause and solution

Possible cause

What you can do

A Firefox error or the ATO’s Security Certificate has expired / is not yet valid
  1. Select ‘I understand the risks’ and/or 'Advanced'.
  2. Select ‘Add Exception’.
  3. Pause and select ‘Confirm Security Exception’ (this setting only applies to the Government Authentication Service).
  4. If you are unable to select ‘Confirm Security Exception’ then clear the cache and cookies in your web browser and try again.

Access denied / Existing or new session detected

Possible cause and solution

Possible cause

What you can do

Multiple sessions running or bad connection

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Try using a different device.

Session Expired

Possible cause and solution

Possible cause

What you can do

Session has timed out

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Make sure the date, time, and time zone are set to Australia.

  • Windows: select date/time in the bottom right corner of your screen.
  • Mac: select date/time in the top right corner of your screen.

Restart your computer.

404 File or directory not found

Possible cause and solution

Possible cause

What you can do

The resource has been removed, changed name or is temporarily unavailable

Check your computer is connected to the internet. If you are unable to connect to the internet, contact your internet service provider.

Refresh the web page (Windows: 'Ctrl + F5' or MAC: 'Command + R').

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

If your computer is connected to a business network, contact your internal IT support.

HTTP 403 Forbidden

Possible cause and solution

Possible cause

What you can do

The URL requested is denied due to security configuration

Check your computer is connected to the internet. If you are unable to connect, contact your internet service provider.

If your computer is connected to a business network, speak with your internal IT support to check if the website is blocked.

Clear the cache and cookies in your web browser and try again.

Try an alternative supported web browser such as Firefox or Chrome.

Check if there is a firewall.

Unable or failed to print

Possible cause and solution

Possible cause

What you can do

Adobe reader is incorrectly set, has known issues with printing or is using an incorrect print process
  1. Make sure the printer is turned on and run a test by printing from another software program such as Word.
  2. Make sure the correct printer is selected in print settings.
  3. Print using the Microsoft XPS writer by  
    • changing the printer to 'Microsoft XPS Document Writer' in print settings, this should prompt to 'Save' the document on PC
    • opening the saved XPS file separately and printing from the XPS document viewer instead – the XPS document must be opened with Internet Explorer or XPS viewer – if Internet Explorer is not the default browser and you are using a computer mouse, you can right click on the XPS document, left click 'Open with' and select XPS viewer or Internet Explorer.

Online services system requirements check tool returns compatibility issues

Possible cause and solution

Possible cause

What you can do

Device is not compatible
  1. Make sure your browser meets the minimum requirements. If you are using a mobile device, the browser will need to be updated to meet minimum requirements via the App Store (iOS) or Play Store (android).
  2. Enable JavaScript:  
  3. Accept Cookies:  
  4. Check your computer is connected to the internet. If you are unable to connect to the internet, contact your internet service provider or use another network (if applicable).

Enable JavaScript

How to enable JavaScript – desktop browsers using Chrome

To enable JavaScript – desktop browsers using Chrome:

  1. On your computer, open Chrome.
  2. At the top right, select the 3 vertical dots.
  3. Select 'Settings'.
  4. At the bottom, select 'Advanced.'
  5. Under 'Privacy and security', select 'Content settings'.
  6. Select JavaScript.
  7. Turn on 'Allowed (recommended)'.

How to enable JavaScript – desktop browsers using Firefox

To enable JavaScript – desktop browsers using Firefox:

  1. Select the 3 horizontal lines in the top right corner.
  2. Select 'Help'.
  3. Select 'Troubleshooting Information'.
  4. Select 'Refresh Firefox' in the top right corner.

How to enable JavaScript – desktop browsers using Internet Explorer

To enable JavaScript – desktop browsers using Internet Explorer:

  1. Select the cog in the top right corner.
  2. Select 'Internet Options'.
  3. Select the 'Security' tab.
  4. Select 'Custom level'.
  5. Scroll down to Scripting. Under 'Active Scripting', set it to 'Enable'.

How to enable JavaScript – desktop browsers using Edge

JavaScript cannot be disabled in Edge.

How to enable JavaScript – desktop browsers using Safari

To enable JavaScript – desktop browsers using Safari:

  1. Select 'Safari' along the top menu bar.
  2. Select 'Preferences'.
  3. Select 'Security'.
  4. Select the 'Enable JavaScript' checkbox to enable it and try again.

How to enable JavaScript – mobile browsers using Safari for iOS

How to enable JavaScript – mobile browsers using Safari for iOS:

  1. Navigate to the 'Settings' app.
  2. On the left-hand bar, select 'Safari'.
  3. Scroll to the bottom and select 'Advanced'.
  4. Enable 'Javascript'.

How to enable JavaScript – mobile browsers using Chrome for Android

How to enable JavaScript – mobile browsers using Chrome for Android:

  1. Open Chrome.
  2. Select the 3 vertical dots in the top right corner.
  3. Select 'Settings'.
  4. Select 'Content Settings'.
  5. Enable 'Enable Javascript'.

Accept cookies

How to accept Cookies – desktop browsers using Chrome

How to accept Cookies – desktop browsers using Chrome:

  1. On your computer, open Chrome.
  2. At the top right, select the 3 vertical dots.
  3. Select 'Settings'
  4. At the bottom, select 'Advanced'.
  5. Under ‘Privacy and security’, select 'Content settings'.
  6. Select 'Cookies'.
  7. Turn on ‘Allow sites to save and read cookie data’.

How to accept Cookies – desktop browsers using Firefox

How to accept Cookies – desktop browsers using Firefox:

  1. At the top right, select the 3 horizontal lines.
  2. Select 'Settings' or 'Options'.
  3. Select 'Privacy & Security'.
  4. In the drop-down menu in the History section choose 'Remember history'.

NOTE: If this is set to 'Use Custom Settings', an additional menu will expand, and you can select 'Accept cookies from websites'.

How to accept Cookies – desktop browsers using Internet Explorer

How to accept Cookies – desktop browsers using Internet Explorer:

  1. Select the gear in the top right corner.
  2. Select 'Internet Options'.
  3. Select the 'Privacy' tab.
  4. Select 'Advanced'.
  5. Set 'First-party Cookies' to 'Allow', set 'Third-party cookies' to 'Block'.
  6. Check the box for 'Always allow session cookies'.

How to accept cookies – desktop browsers using Edge

How to accept cookies – desktop browsers using Edge:

  1. Select the 3 horizontal dots in the top right corner.
  2. Select 'Settings'.
  3. Select 'View advanced settings'.
  4. Under the Cookies section, select to either 'Don't block cookies'. (default) or 'Block only third-party cookies'.
  5. Restart Edge and try again.

How to accept Cookies – desktop browsers using Safari

How to accept Cookies – desktop browsers using Safari:

  1. Select 'Safari' along the top menu bar.
  2. Select 'Preferences'.
  3. Select 'Privacy'.
  4. Uncheck the box that says 'Block all cookies' under Cookies and website data.

How to accept Cookies – mobile browsers using Safari for iOS

How to accept Cookies – mobile browsers using Safari for iOS:

  1. Navigate to the 'Settings' app.
  2. On the left-hand bar, select 'Safari'.
  3. Ensure 'Block All Cookies’ is disabled.

How to accept Cookies – mobile browsers using Chrome for Android

How to accept Cookies – mobile browsers using Chrome for Android:

  1. Open Chrome.
  2. Select the 3 vertical dots in the top right corner.
  3. Select 'Settings'.
  4. Select 'Content Settings'.
  5. Enable 'Accept Cookies'.

Server not found

Possible cause and solution

Possible cause

What you can do

ATO online services outage or error

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

If you are using Internet Explorer add trusted zones for ato.gov.au, (as well as abr.gov.au External Linkand business.gov.auExternal Link if you are a business user), then close all browsers and try again.

Check your computer is connected to the internet. If you are unable to connect, contact your internet service provider.

Restart your computer.

Try an alternative supported web browser such as Firefox or Chrome.

System has timed out

Possible cause and solution

Possible cause

What you can do

Website has been idle for too long

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Clear the cache and cookies in your web browser and try again.

Your connection is not private

Possible cause and solution

Possible cause

What you can do

Your browser cannot verify if a website is safe to visit

Select ‘Advanced’ to proceed.

Select ‘Proceed to [website] (unsafe)’ link at the bottom of the message if it appears.

If issue persists, clear the cache and cookies in your web browser and try again.

Login timeout

Possible cause and solution

Possible cause

What you can do

Session has expired

Go back to the login page of the service you were trying to access. Try logging in again with your Digital ID, such as myID.

If you continue to experience issues, clear the cache and cookies in your web browser, close the browser and try to login again.

If you are using Firefox, login with another supported browser such as Chrome, and then attempt to login with Firefox again.

Error downloading PDF files

Possible cause and solution

Possible cause

What you can do

Restricted browser settings or firewalls

If you use a computer mouse, right click on the PDF download link.

Select the 'Save link as' or 'Save target as'.

Choose a location on your PC where you will download to, give the file a name and click the Save button.

When the download completes you will be able to open the PDF file with a suitable PDF viewer.

ATO Online URL check and Network Test

Possible cause and solution

Possible cause

What you can do

Software or network settings may be blocking a page from loading

Perform the ATO online URL check:

  1. Select this link https://onlineservices.ato.gov.au/cdn/cdntest.txtExternal Link or copy and paste it into the address bar of your browser and press ‘Enter’.
  2. If you cannot access this page, add the URL 'atoonlinecdnstream.azureedge.net' to the whitelist within your proxy or firewall.
  3. If the URL check returns the message 'ATO CDN Working' then go back to ATO online services and try to reload the screen that was not working.

Perform a network test:

  1. Disconnect your device from the current network and connect it to an alternative internet source such as another network or mobile hotspot.
  2. Try to reload the screen within ATO online services which was not loading. If the screen loads properly and you were previously connected to a business network, contact your internal IT support.

MC005

Possible cause and solution

Possible cause

What you can do

An old session is used when attempting to authenticate

Refresh the web page (Windows: ‘Ctrl + F5’ or Mac: ‘Command + R’).

Close all sessions of the browser and open a new browser window.

Clear the cache and cookies in your web browser and try again.

ATOBE.PKG can't be opened

Possible cause and solution

Possible cause

What you can do

Restricted browser settings or server issues
  1. Check if the error message has an ‘Open’ button.
  2. If there is no ‘open’ button and you have a computer mouse, right click on ‘ATOBEinstaller.pkg’ and click ‘Open’. You should now see an ‘Open’ button on the error message.
  3. After clicking ‘Open’, the program should install successfully.

Note: This error only occurs in Mac operating systems.

Security certificate not valid

Possible cause and solution

Possible cause

What you can do

The ATO’s Security Certificate has expired or is not yet valid

Select ‘Continue to this website’ if the prompt shows up on the page.

Publisher could not be verified

Possible cause and solution

Possible cause

What you can do

Running an executable file on Windows XP or higher a security warning will be displayed

Confirm that you wish to run the program. If so, select ‘Run’ on the security warning pop up message.

Firefox or Chrome is running

Possible cause and solution

Possible cause

What you can do

Firefox or Chrome is running and needs to be closed

Firefox:

  1. Close all active Firefox browser windows and re-open Firefox again.
  2. Open the Windows Task Manager (Ctrl+Shift+Esc)
  3. Restart your computer and try again.

Chrome:

  1. Close all active Chrome browser windows and re-open Chrome again.
  2. Open the Windows Task Manager (Ctrl+Shift+Esc)  
    • Select the ‘Processes’ tab
    • Select any chrome.exe*32 processes and select ‘End task’
    • Once the list is clear of all Chrome processes, close the Windows Task Manager and try the browser again.

3. Restart your computer and try again.

This publisher has been blocked

Possible cause and solution

Possible cause

What you can do

Windows blocks the installation of the ATOBE extension software
  1. Close the ‘Windows protected your PC’ warning box if it is still open.
  2. Locate the file you downloaded. If you cannot find the file, go back to the ATO Browser ExtensionExternal Link page and download the ‘Windows’ extension again. Make sure you save this file to your downloads folder or desktop.
  3. If you use a computer mouse, right click on the file, then select ‘Properties’.
  4. Select the ‘General’ tab, check the ‘Unblock’ box at the bottom, then select OK.
  5. If prompted, select ‘Continue’, and select ‘Yes’ (you are the administrator) or enter password of administrator.
  6. When you have completed the above steps, if you use a computer mouse double click on the downloaded file (atobeInstaller.exe) to attempt the installation again.
  7. If the above steps fail, or if the 'Unblock' option does not appear, clear the cache and cookies in your web browser and try again.

Buttons missing within ATO Online Services

Possible cause and solution

Possible cause

What you can do

Device may not be compatible

Check your device is compatible using the ATO online services system requirements check.

Try an alternative supported web browser such as Firefox or Chrome.

If you are using Internet Explorer, select the cog icon and select 'Settings'. Make sure that no ato.gov.au page is under the compatibility view list. If it is, select it, then select remove. If the error persists, unselect 'Use Microsoft compatibility lists'.

Slow download or download dropping out

Possible cause and solution

Possible cause

What you can do

Slow download speed

Windows:

Mac:

  • Try to download the file again later.
  • Try an alternative supported web browser such as Chrome or Firefox.

Page or website blocked

Possible cause and solution

Possible cause

What you can do

Browser settings or Firewalls

Refresh the web page (Windows: ‘Ctrl + F5’; Mac: ‘Command + R’).

Try an alternative supported web browser such as Firefox or Chrome.

Clear the cache and cookies in your web browser and try again.

Add ato.gov.au as a trusted site in Internet Explorer.

Connection to server was reset

Possible cause and solution

Possible cause

What you can do

Internet connection lost or disrupted

Refresh the web page.

Clear the cache and cookies in your web browser and try again.

Restart your computer.

Mozapps error: the add-on downloaded from this site could not be installed because it appears to be corrupt

Possible cause and solution

Possible cause

What you can do

Occurs when trying to install ATOBE add-on to Firefox from file instead of running ATOBEinstaller.exe
  1. Download and reinstallExternal Link the ATOBE software.
  2. Run the ATOBE installer from your computer. If the error persists, use an alternative supported web browser such as Chrome or Edge.

Display issues (Graphics)

Possible cause and solution

Possible cause

What you can do

Various
  1. Ensure the browser meets supported requirements for the ABR system.
  2. Make sure that your screen resolution is set to a minimum of 1024 x 768.
  3. Refresh the web page (Windows: ‘Ctrl + F5’ or MAC: ‘Command + R’).
  4. Close and reopen your web browser.

Browser blocking download

Possible cause and solution

Possible cause

What you can do

Your computer security setting blocked the file
  1. If you use a computer mouse, right click on the link and select ‘Save as’ or ‘Save target as’.
  2. Select ‘Desktop’ and select ‘Save’.

This site can’t be found or reached / Website or service temporarily unavailable / Problem accessing the site /

Possible cause and solution

Possible cause

What you can do

Unable to locate the requested URL

Check your computer is connected to the internet. If you are unable to connect, contact your internet service provider.

Clear the cache and cookies in your web browser and try again.

Check our system maintenance page for outage notifications.

If your computer is connected to a business network, contact your internal IT support.

Application server error / Connection timed out

Possible cause and solution

Possible cause

What you can do

Unable to locate the requested URL

Check your computer is connected to the internet. If you are unable to connect, contact your internet service provider.

Clear the cache and cookies in your web browser and try again.

Check our system maintenance page for outage notifications.

If your computer is connected to a business network, contact your internal IT support.

 



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