Microsoft 365 Error Codes

How to Fix Microsoft 365 Error 0xCAA70004 (Proxy Authentication)

Huma Ashraf Ch Oct 10, 2026 870 views

Question details

The user is unable to sign in to Microsoft 365 applications using a school account and receives an error code related to proxy authentication.

How to Fix Microsoft 365 Error 0xCAA70004 and Proxy Authentication Issues

Product: Microsoft 365
Device & OS: not provided
Scenario: Signing in to Microsoft 365 desktop apps with a work or school account.
Observed behavior: The application fails to sign in, displaying error code 0xCAA70004 alongside a proxy authentication message.

Before you start

Ensure you have your correct school or work account credentials ready and verify that your device is connected to a stable internet network before modifying account settings.

Solution 1Recommended

Disconnect and Reconnect Your Work or School Account

Refreshing the connection between your device and your Microsoft 365 account often resolves authentication glitches causing the 0xCAA70004 error.

Windows stores work and school account credentials locally. If the authentication token becomes corrupted or out of sync with the server, clearing and reconnecting it can bypass proxy errors.

Close Office Applications

Ensure all Microsoft Office applications (such as Word, Excel, and Teams) are completely closed.

Access Windows Settings

Open your Windows Settings, navigate to the Accounts section, and select Access work or school from the side menu.

Disconnect the Account

Locate your Microsoft 365 school or work account in the list, select it, and click Disconnect.

Restart Your Device

Restart your computer to completely clear any cached authentication data from the system.

Reconnect the Account

Go back to Settings > Accounts > Access work or school, click Connect to add your Microsoft 365 account again, and attempt to sign in to your Office apps.

Disconnect and Reconnect Your Work or School Account

Account Not Listed: If you do not see your account listed in the Access work or school menu initially, simply click Connect to add it, restart your device, and try signing in again.

Solution 2

Reset the Microsoft 365 Apps Activation State

If reconnecting the account does not resolve the issue, resetting the Office activation state clears corrupted local license configurations.

Free Microsoft Office alternative

Use WPS Office to Access Your Documents Without Sign-in Errors

If persistent Microsoft 365 authentication errors are preventing you from doing your schoolwork or office tasks, WPS Office offers a free, lightweight, and highly compatible alternative that does not rely on complex proxy authentications to edit local files.

1. Download the Installer: Visit the official WPS Office website and download the free installation package for your operating system.
2. Install WPS Office: Run the downloaded installer and follow the quick on-screen instructions to set up the software.
3. Open Your Documents: Launch WPS Office and open your existing Microsoft Office files directly to continue your work without interruptions.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats (.docx, .xlsx, .pptx).Edit and save your local documents immediately without complex proxy or sign-in requirements.Free to use with a familiar user interface, ensuring zero learning curve.Lightweight installation that runs smoothly even on older devices.

microsoft office alternative - wps office

Frequently Asked Questions

What does Microsoft 365 error 0xCAA70004 mean?

This error typically indicates a network or proxy authentication issue that prevents Microsoft 365 applications on your device from securely communicating with the Microsoft sign-in servers.

Does error 0xCAA70004 affect all Microsoft 365 applications?

Yes. Because Microsoft 365 desktop applications (like Word, Excel, PowerPoint, and Teams) share the same underlying authentication credentials, a proxy error will generally prevent you from signing in to all of them.

What should I do if the standard troubleshooting steps fail?

If resetting the account and activation state does not work, the issue may stem from your institution's network proxy settings. You should contact your school or work IT administrator to create a support ticket with Microsoft.

Microsoft Office Error Codes