office 365 error when registration

The error details (correlation ID, tag 4wp0s, code -2146893805, “An unexpected error occurred”) indicate a backend or authentication failure during Microsoft 365 registration/sign-in. The exact root cause can only be determined from server-side logs using the correlation ID, but the standard remediation steps for unexpected Microsoft 365 sign-in/activation issues are:

1. Update Windows
2. From Start, type Check for updates and select it.
3. Choose Check for updates.
4. Install all available updates.
5. Restart the device and attempt the Microsoft 365 registration/sign-in again.
6. Clear cached Office credentials
7. From Start, type Credential Manager and open it.
8. Select Windows credentials.
9. Find any entries named MicrosoftOffice16 and select Remove for each.
10. Close Credential Manager.
11. Open Settings > Accounts > Access work or school.
12. If the Microsoft 365 account used for registration appears there and is different from the Windows sign-in account, select it and choose Disconnect.
13. Restart the device and retry the registration/sign-in.
14. Check AAD BrokerPlugin and security software

Some sign-in/activation flows rely on the Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy process. If this is blocked, unexpected errors can occur.

1. Ensure antivirus, firewall, proxy, or VPN are not blocking Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy.
2. Temporarily disable antivirus and VPN.
3. If behind a corporate proxy or firewall, ask the IT administrator to verify that this process and Microsoft 365 endpoints are allowed.
4. Try the registration/sign-in again.
5. Reset Microsoft 365 activation/sign-in state

Follow the procedure in Reset activation state for Microsoft 365 Apps for enterprise to clear existing activation/identity data, then sign in or register again.

5. Delete BrokerPlugin token data and run the sign-in troubleshooter

If the problem persists, clear the local token cache used by the BrokerPlugin and Cloud Experience Host, then use the Microsoft 365 sign-in troubleshooter.

1. Open File Explorer and paste:
   • %LOCALAPPDATA%\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\AC\TokenBroker\Accounts
   • Press Ctrl+A to select all files, then delete them.
2. Next, open:
   • %LOCALAPPDATA%\Packages\Microsoft.Windows.CloudExperienceHost_cw5n1h2txyewy\AC\TokenBroker\Accounts
   • Select all files and delete them.
3. Restart the device.
4. Run the Microsoft 365 sign-in troubleshooter in Get Help (as referenced at https://aka.ms/SaRA-OfficeSignIn-sarahome) and follow its guidance.
5. If the error occurs during Office app activation

If this unexpected error appears while activating Office apps, follow the full sequence documented for activation error 0x80070005:

• Update Windows (already covered above).
• Reset the Microsoft 365 activation state.
• Remove Office credentials (steps above).
• Verify Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy is not blocked.
• If still failing, rename tokens.dat and repair Office:
  1. Open Command Prompt as administrator.
  2. Run: net stop sppsvc.
  3. In File Explorer, go to %SystemDrive%\Windows\System32\spp\store\2.0.
  4. Right-click tokens.dat and rename it to tokens.old.
  5. In Command Prompt, run: net start sppsvc.
  6. Perform an online repair of Office as described in the documentation.
  7. Restart the device and try activation again.

7. Escalation with correlation ID

If all of the above steps fail, the issue is likely on the service side or tenant configuration. Provide the following to the Microsoft 365 or Microsoft Entra administrator or to Microsoft support so they can trace the failure in backend logs:

• Correlation Id: 9df7ba36-cf41-4b5e-a502-2990b72fcead
• Timestamp: 2026-03-04T12:28:04.000Z
• Code: -2146893805
• Message: An unexpected error occurred.

They can then investigate the exact cause and apply any tenant- or service-level fixes required.

References:

• Microsoft 365 Apps activation error 0x80070005
• Microsoft 365 Apps activation error 0xCAA50021
• Microsoft 365 Apps activation error "AADSTS9002313: Invalid Request"
• Microsoft 365 Apps activation error codes 0xCAA70007 and 0xCAA80000
• Office error code 0x80070005 when activating Office