Login Failure in Teams Desktop App - Error Code: 3399811147 (Tag: 7ita9)

Question

Hello,

I am experiencing an issue logging into the Microsoft Teams desktop application on Windows 10. When I attempt to sign in, the process fails and displays an "Unexpected error."

However, I can successfully log in to the Teams web version (browser) without any issues, which suggests the problem is isolated to the desktop client or the local authentication broker.

Here are the specific error details from the application:

Error Code: 3399811147

• Tag: 7ita9 Correlation Id: [Moderator note: personal info removed]  Timestamp: 2025-12-17T12:26:37.000Z DPTI: [Moderator note: personal info removed]  Message: An unexpected error occurred.

I have already tried restarting/reistalling the application, but the issue persists. Please advise on the next steps to resolve this desktop client authentication error.

Thank you.

Answer 1

To resolve the login failure in the Microsoft Teams desktop application with the error code 3399811147, you can follow these troubleshooting steps:

1. Check for Updates: Ensure that your Teams client is updated to the latest version. You can check for updates by selecting the Settings and more menu next to your profile picture in Teams and then selecting Check for updates.
2. Clear Teams Cache: Sometimes, clearing the Teams cache can resolve unexpected errors. To do this:
   • Close Microsoft Teams.
   • Navigate to the %appdata%\Microsoft\Teams folder on your computer.
   • Delete all the files and folders in this directory.
   • Restart Teams and try to sign in again.
3. Reinstall Teams: If the issue persists, try uninstalling and then reinstalling the Teams application. Make sure to uninstall it completely and remove any leftover files in the %appdata%\Microsoft folder.
4. Check Internet Connection: Since you can log in via the web version, ensure that your desktop client has a stable internet connection and is not being blocked by firewall or security software.
5. Review Security Software: If you have security software installed, it may interfere with the Teams login process. Temporarily disable it or configure it to allow Teams.
6. Use Administrator Account: Try running Teams as an administrator. Right-click the Teams shortcut and select Run as administrator.
7. Collect Logs: If none of the above steps work, consider collecting debug logs and creating a support request with Microsoft. You can find guidance on how to collect logs here.

If the problem continues after trying these steps, you may need to contact Microsoft support for further assistance.

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References:

• Resolve sign-in errors in Teams
• Can't sign in to Microsoft 365 desktop applications

Answer 2

Hi @Marcin, 

Thank you for posting your question in the Microsoft Q&A forum. To protect your privacy and ensure the security of your personal information, I’ve removed any sensitive details from your public post and sent you a private message. You can check your private messages by clicking the banner at the top of the page, as shown in the image below: 

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Based on my research, error 3399811147 typically occurs when the Teams desktop client fails to authenticate, even though web-based sign-in works. This usually points to an issue with the Windows Account Manager (WAM) authentication broker since your account functions correctly in the browser. 

Please try these initial troubleshooting steps first: 

• Step 1: Repair Windows Account Manager (WAM). To re-register the authentication broker component, open Windows PowerShell by typing PowerShell in the search bar, then right-click and select Run as administrator. Copy and paste the following command for work or school accounts: 

Add-AppxPackage -Register "$env:windir\SystemApps\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\Appxmanifest.xml" -DisableDevelopmentMode –ForceApplicationShutdown

Press Enter and wait for completion. After that, run this second command: 

Add-AppxPackage -Register "$env:windir\SystemApps\Microsoft.Windows.CloudExperienceHost_cw5n1h2txyewy\Appxmanifest.xml" -DisableDevelopmentMode –ForceApplicationShutdown

Once both commands have finished, close PowerShell. 

• Step 2: Disconnect and your account. Go to Settings > Accounts > Access work or school. Locate your work or school account, click on it, and select Disconnect. Confirm the removal when prompted. 

• Step 3: Clear Windows Credential Manager. Open Credential Manager by searching for it in Windows. Select Windows Credentials, then look for and remove any entries related to MicrosoftOffice16_Data, Outlook, Office365, or your email address. 

After completing these steps, restart your computer and try signing in to Teams again. 

As a forum moderator, I don’t have access to backend tools or permissions to investigate the root cause directly. If these troubleshooting steps don’t resolve the issue, please reply to this thread. I’ll be happy to research further and suggest alternative actions that may help. 

Thank you so much for your patience and understanding

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