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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 2 December 2025

A system error has occurred

Possible cause

ATO online services outage or error.

What you can do

Browser crashes, closes or page hangs

Possible cause

Server has timed out or internet connection issues.

What you can do

  • 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 or 5G (not to an office or corporate Wi-Fi).
  • If you're using a business security solution, such as VPN, contact your internal IT support.

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

Site under maintenance or under construction

Possible cause

Website is being updated.

What you can do

Unexpected error or Process error or Internal error

Possible cause

ATO online services outage or software issue.

What you can do

  • Check our system maintenance page for outage notifications.
  • 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 Firefox, make sure you enable Remember history
    • 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.

Error: Function unavailable or Unknown Error

Possible cause

ATO online services outage or error.

What you can do

Error: PRX-(###) proxy error

Possible cause

Internal connectivity or network issues within ATO systems. This may result in error codes that begin with PRX, followed by 3 digits (for example, PRX-001, PRX-002, PRX-003, PRX-010, PRX-019).

What you can do

  • Refresh the web page (Windows: Ctrl + F5 or Mac: Command + R).
  • Close and reopen the browser and try again.
  • Check our system maintenance page for outage notifications.
  • Try an alternative supported web browser such as Firefox or Chrome.
  • Try again later.

Error opening file for writing or autorun.inf

Possible cause

Firewalls.

What you can do

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

This connection is untrusted or Your connection is not secure

Possible cause

A Firefox error or the ATO’s Security Certificate has expired or is not yet valid.

What you can do

  1. Select I understand the risks or Advanced (or both).
  2. Select Add Exception.
  3. Pause and select Confirm Security Exception (this setting only applies to the Government Authentication Service).

If you're unable to select Confirm Security Exception then clear the cache and cookies in your web browser and try again.

Access denied or Existing or new session detected

Possible cause

Multiple sessions running or bad connection.

What you can do

Session expired

Possible cause

Session has timed out.

What you can do

  • 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 the date and time in the bottom right corner of your screen
    • Mac – select the date and time in the top right corner of your screen.
  • Restart your computer.

404 File or directory not found

Possible cause

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

What you can do

  • Check your computer is connected to the internet. If you're 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

The URL requested is denied due to security configuration.

What you can do

  • Check your computer is connected to the internet. If you're 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

Adobe reader is incorrectly set, has known issues with printing or is using an incorrect print process.

What can you do

  • Make sure the printer is turned on and run a test by printing from another software program such as Word.
  • Check that the correct printer is selected in the Print settings.
  • Try printing using the Microsoft XPS writer
  • Change the printer to Microsoft XPS Document Writer in Print settings
    • select Print – this will prompt you to Save the document to your PC
    • right click on the saved XPS document
    • left click Open with, and
    • select XPS viewer or Internet Explorer
    • then select Print.

Online services system requirements check tool returns compatibility issues

Possible cause

Device is not compatible.

What can you do

Enable JavaScript

How 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
  1. Open Firefox.
  2. Select the 3 horizontal lines in the top right corner.
  3. Select Help.
  4. Select Troubleshooting Information.
  5. Select Refresh Firefox in the top right corner.
How to enable JavaScript – desktop browsers using Internet Explorer
  1. Open Internet Explorer.
  2. Select the cog icon in the top right corner.
  3. Select Internet options.
  4. Select the Security tab.
  5. Select Custom level.
  6. Scroll down to Scripting. Under Active scripting, set it to Enable.
How to enable JavaScript – desktop browsers using Edge

JavaScript can't be disabled in Edge.

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

Accept cookies

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
  1. Open Firefox.
  2. At the top right, select the 3 horizontal lines.
  3. Select Settings or Options.
  4. Select Privacy & Security.
  5. 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
  1. Open Internet Explorer.
  2. Select the gear in the top right corner.
  3. Select Internet options.
  4. Select the Privacy tab.
  5. Select Advanced.
  6. Set First-party Cookies to Allow, set Third-party cookies to Block.
  7. Check the box for Always allow session cookies.
How to accept cookies – desktop browsers using Edge
  1. Open Edge.
  2. Select the 3 horizontal dots in the top right corner.
  3. Select Settings.
  4. Select View advanced settings.
  5. Under the Cookies section, select either Don't block cookies (default) or Block only third-party cookies.
  6. Restart Edge and try again.
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
  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

Accepting 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

ATO online services outage or error.

What you can do

System has timed out

Possible cause

Website has been idle for too long.

What you can do

Your connection is not private

Possible cause

Your browser can't verify if a website is safe to visit.

What you can do

  1. Select Advanced to proceed.
  2. Select Proceed to [website] (unsafe) link at the bottom of the message if it appears.

If the issue persists:

Login timeout

Possible cause

Session has expired.

What you can do

  • Go back to the login page of the service you were trying to access and try logging in again with your Digital ID, such as myID.
  • Clear the cache and cookies in your web browser, close the browser and try to log in again.
  • If you're using Firefox, log in with another supported browser such as Chrome, and then attempt to log in with Firefox again.

Error downloading PDF files

Possible cause

Restricted browser settings or firewalls.

What you can do

  1. If you use a computer mouse, right click on the PDF download link.
  2. Select the Save link as or Save target as.
  3. Choose a location on your PC where you will download to, give the file a name and click Save.
  4. When the download completes open the PDF file with a suitable PDF viewer.

ATO online URL check and Network test

Possible cause

Software or network settings may be blocking a page from loading.

What you can do

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 can't 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

An old session is used when attempting to authenticate.

What you can do

ATOBE.PKG can't be opened

Possible cause

Restricted browser settings or server issues.

This error only occurs in Mac operating systems.

What you can do

  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 select Open. You should now see an Open button on the error message.
  3. After clicking Open, the program should install successfully.

Security certificate not valid

Possible cause

The ATO’s security certificate has expired or is not yet valid.

What you can do

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

Publisher could not be verified

Possible cause

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

What you can do

  1. Confirm if you wish to run the program.
  2. If yes, select Run on the security warning pop-up message.

Firefox or Chrome is running

Possible cause

Firefox or Chrome is running and needs to be closed.

What you can do

Using Firefox

  1. Close all active Firefox browser windows and re-open Firefox again.
  2. Open the Windows Task Manager by pressing Ctrl + Shift + Esc.
  3. Select the Processes tab.
  4. Select any firefox.exe processes and select End task.
  5. Once the list is clear of all Firefox processes, close the Windows Task Manager and try the browser again.
  6. Restart your computer and try again.

Using Chrome

  1. Close all active Chrome browser windows and re-open Chrome again.
  2. Open the Windows Task Manager by pressing Ctrl + Shift + Esc.
  3. Select the Processes tab.
  4. Select any chrome.exe*32 processes and select End task.
  5. Once the list is clear of all Chrome processes, close the Windows Task Manager and try the browser again.
  6. Restart your computer and try again.

This publisher has been blocked

Possible cause

Windows blocks the installation of the ATOBE extension software.

What you can do

  1. Close the Windows protected your PC warning box if it is still open.
  2. Locate the file you downloaded. If you can't 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 these steps fail, or if the Unblock option doesn't appear, clear the cache and cookies in your web browser and try again.

Buttons missing within ATO online services

Possible cause

Device may not be compatible.

What you can do

If you are using Internet Explorer

  1. Select the cog icon.
  2. Select Settings.
  3. Check if any ato.gov.au page is listed under the compatibility view list. If yes, select it, then click remove.
  4. If the error persists, unselect Use Microsoft compatibility lists.

Slow download or download dropping out

Possible causes

Slow download speed.

What you can do

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

Browser settings or firewalls.

What you can do

  • 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

Internet connection lost or disrupted.

What you can do

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

Possible cause

Occurs when trying to install ATOBE add-on to Firefox from file instead of running ATOBEinstaller.exe.

What you can do

  1. Download and reinstallExternal Link the ATOBE software.
  2. Run the ATOBE installer from your computer.
  3. If the error persists, use an alternative supported web browser such as Chrome or Edge.

Display issues (Graphics)

Possible cause

Various.

What you can do

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

Browser blocking download

Possible cause

Your computer security setting blocked the file.

What you can do

  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 or Website or service temporarily unavailable or Problem accessing the site

Possible cause

Unable to locate the requested URL.

What you can do

  • Check your computer is connected to the internet. If you're 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 or Connection timed out

Possible cause

Unable to locate the requested URL.

What you can do

  • Check your computer is connected to the internet. If you're 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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