Error Code CAA20002 | How to Fix

Error Code CAA20002 is commonly associated with Microsoft Teams, and typically indicates a sign-in or authentication issue, often caused by a problem with the Office credentials, Windows account settings, or network configuration.

Here’s a step-by-step guide to fix CAA20002:

✅ 1. Clear Teams Cache

This fixes many local sign-in errors.

• Close Microsoft Teams completely.

• Press Windows + R, type:

  shell

  %appdata%\Microsoft\Teams


• Delete all files and folders in that directory.

• Restart Teams.

✅ 2. Sign Out and Re-sign In to Office

• Open any Office app (like Word or Outlook).

• Sign out of your account.

• Sign back in using the same credentials you use for Teams.

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✅ 3. Check Internet and Proxy Settings

• Ensure your internet is stable.

• If you’re using a VPN or proxy, try disabling it temporarily.

• Go to Settings > Network & Internet > Proxy and turn off any manual proxy setup.

✅ 4. Reset Windows Account Credentials

• Open Windows Credentials Manager:
  Control Panel > User Accounts > Credential Manager.

• Under Windows Credentials and Generic Credentials, remove any entries related to Microsoft Teams or Office.

• Restart your PC.

✅ 5. Update Teams and Windows

• Ensure Microsoft Teams is up to date.

• Go to Settings > Update & Security > Windows Update and install any pending updates.

✅ 6. Reinstall Teams

If none of the above work:

• Uninstall Teams from Apps & Features.

• Delete cache again using %appdata%\Microsoft\Teams.

• Reboot and reinstall the latest version of Teams from Microsoft’s official site.

✅ 7. Check for Azure AD or Conditional Access Issues (Enterprise/Org Users)

If you’re on a work/school account:

• Your organization may have Conditional Access policies or Azure AD issues.

• Contact your IT administrator to verify if your device or location is being blocked.

Advanced Troubleshooting for Error Code CAA20002

🧠 8. Check for Account Conflicts (Multiple Accounts)

• If you’ve signed into Teams (or other Office apps) with multiple Microsoft accounts, that can cause token or identity confusion.

• Open any Office app (e.g., Outlook), go to:

  • File > Account

  • Remove any extra accounts not currently in use.

Also, in Windows Settings:

• Go to Settings > Accounts > Access work or school

• Remove any duplicate or outdated accounts.

🔧 9. Reset Teams Using PowerShell (for persistent issues)

Use this command to completely remove Teams configuration:

Then re-download and reinstall Teams.

🔐 10. Check Device Registration with Azure AD

If you’re part of a work/school organization, your PC may be blocked or not registered properly in Azure Active Directory (AAD):

• Open Command Prompt and run:

Check the output:

• AzureADJoined or DomainJoined should be YES

• If it’s NO, your device might not be properly enrolled, causing auth issues.

Ask IT or your admin to re-register the device or use dsregcmd /join with admin rights.

🔄 11. Disable Modern Authentication Temporarily (Admin-Level)

If you’re an admin or managing a tenant:

• Sometimes legacy systems misbehave with Modern Auth.

• You can temporarily disable Modern Auth for testing via Microsoft 365 Admin Center or PowerShell.

• Note: This is not recommended long-term, only for diagnosing the issue.

🧰 12. Review Sign-in Logs in Microsoft Entra (Azure AD)

For enterprise environments:

• Go to https://entra.microsoft.com

• Check Sign-in Logs for the affected user under Monitoring > Sign-ins

• Look for the actual reason for failure (often more detailed than just CAA20002)

📡 13. Inspect Firewall or Antivirus Blocking

Some endpoint protection software (e.g., McAfee, Kaspersky, Palo Alto agents) may block Teams authentication or token access.

• Temporarily disable firewall/AV to test

• Whitelist these URLs if needed:

  • *.teams.microsoft.com

  • *.office365.com

  • login.microsoftonline.com

  • aadcdn.msauth.net