Resolve sign-in errors in Teams

If your users encounter errors when they try to sign in to Microsoft Teams, use the following steps to troubleshoot the problem:

Run the Teams Sign-in diagnostic


This feature requires a Microsoft 365 administrator account. This feature isn't available for Microsoft 365 Government, Microsoft 365 operated by 21Vianet, or Microsoft 365 Germany.

  1. Select the following button to populate the diagnostic in the Microsoft 365 admin center:

  2. In the User Name or Email Address field, enter the email address of the user who's experiencing the Teams sign-in issue.

Use the Microsoft Support and Recovery Assistant (SaRA)

If the diagnostic doesn't detect any issue, but you still can't sign in to Teams, or you don't have a Microsoft 365 administrator account, select the button below to download SaRA and automatically start the tests. For more information about SaRA, see About the Microsoft Support and Recovery Assistant.


By downloading this app, you agree to the terms of the Microsoft Services Agreement and Privacy Statement.

Fix the issue manually

If you want to perform the checks and fix the issue manually, follow these steps:

  1. If the diagnostic detects an issue that affects the instance of Teams on the tenant, follow the provided solution to fix the issue. If the diagnostic doesn't detect an issue, check whether the user's Teams client is running the latest update. Select the Settings and more menu next to the user's profile picture at the top right of the Teams window, and then select Check for updates.

    The desktop app is configured to update automatically. However, if you find that the app is missing the latest update, follow the instructions to install it, and try again to sign in. If you still see an error when you try to sign in to Teams, go to step 3.

  2. If you use a federated sign-in provider such as Active Directory Federation Services (AD FS), verify the AD FS sign-in configuration by using the Microsoft 365 Single Sign-on Test in the Microsoft Remote Connectivity Analyzer.

  3. Check the error code on the Teams sign-in screen. If the code is listed here, follow the provided guidance to fix the error. If the code isn't listed here, see Why am I having trouble signing in to Microsoft Teams?

  4. If the sign-in error occurs only in the Teams web client, see Microsoft Teams is stuck in a login loop for resolutions that are specific to the user's preferred browser.

  5. If the error persists, reinstall Teams as follows:

    1. Uninstall Teams.
    2. Browse to the %appdata%\Microsoft folder on the user's computer, and delete the Teams folder.
    3. Download and install Teams. If possible, reinstall Teams as an administrator. To do this, right-click the Teams installer file, and select Run as administrator.

If none of these steps help to resolve the Teams sign-in issue, create a support request. For the request, collect debug logs, and provide the error code that's displayed on the Teams sign-in screen.