How to Fix Microsoft Teams Sign-in Error CAA50021 on Windows 11 and 10

Are you struggling to sign into your Microsoft Teams account due to the “CAA50021” error code? The “CAA50021” error is a roadblock many Windows 11 (and sometimes Windows 10) users face, hindering their ability to communicate on this essential workplace productivity platform. This in-depth guide will offer actionable troubleshooting tips and techniques to rectify the “CAA50021” error and help you regain seamless access to Microsoft Teams.

What Does the CAA50021 Error in Microsoft Teams Mean?

The CAA50021 error in Microsoft Teams usually signals an issue with the application’s authentication process, often related to corrupted cache files, outdated versions, or network connectivity problems. The good news is there are proven solutions.

Before You Dive In:

  • Internet Connection: Make sure your internet connection is strong and stable. A weak connection can cause sign-in problems.
  • Microsoft Teams Updates: Check for pending Microsoft Teams updates. Outdated versions may lead to compatibility conflicts. The desktop app takes care of updates automatically, saving you the hassle of manual checks. For those who like to take control, you can still check for updates in Teams Classic by selecting the Settings and more menu next to your profile picture at the top right of Teams, and then selecting Check for updates.
Update microsoft teams to solve sign-in error caa50021

Proven Troubleshooting Steps to Fix Microsoft Teams Error CAA50021

Solution 1: The Classic ‘Restart’ Solution

Often the most basic solutions can provide results. Start by restarting your internet router/modem and your computer. Rebooting frequently clears away minor glitches that can interfere with Microsoft Teams.

Solution 2: Clear Microsoft Teams Cache

Should the initial step prove ineffective, clearing the Microsoft Teams cache on Windows is the next course of action. Follow these steps to clear the cache:

  1. Press Windows Key + R to open the Run dialog.
  2. Copy and paste %appdata%\Microsoft\teams\Cache into the text field and press Enter. This opens the File Explorer at the Teams cache location.
  3. Select all files (Ctrl + A) and delete them. Repeat this process for the following directories:
    • %appdata%\Microsoft\teams\application cache\cache
    • %appdata%\Microsoft\teams\blob_storage
    • %appdata%\Microsoft\teams\databases
    • %appdata%\Microsoft\teams\GPUcache
    • %appdata%\Microsoft\teams\IndexedDB
    • %appdata%\Microsoft\teams\Local Storage
    • %appdata%\Microsoft\teams\tmp

Solution 3: Release and Renew IP Address

Network snags can cause authentication hiccups, including the CAA50021 error. Follow these steps to release and renew your IP address in Windows 11:

  1. Search for CMD in the Start menu, right-click Command Prompt, and select Run as administrator.
  2. In the command prompt, type ipconfig /release and press Enter to release the current IP address.
  3. Next, type ipconfig /renew and press Enter to obtain a new IP address.

Solution 4: Remove the Microsoft Teams Credentials

Another way you can try to fix the error CAA50021 is to delete the credentials related to Microsoft Teams.

  1. Open the Control Panel:
    • Click on the Windows search bar or Windows 11 start button Start button.
    • Type Control Panel and press Enter.
  2. Once in the Control Panel, navigate to User Accounts > Manage Windows Credentials.
  3. In the next window, scroll down to find all the credentials associated with Microsoft Teams. Then expand them and click Remove to delete them one by one.
  4. After you delete all the Microsoft Teams credentials, restart your computer to see if the error is resolved.
Remove teams credentials to solve teams error caa50021

Additional Troubleshooting Tips

If the previous steps don’t fix the CAA50021 error, consider these:

  • Check Firewall: Windows Firewall can sometimes block applications. Check your firewall settings and verify that Microsoft Teams is allowed to connect.
  • Temporarily Disable Antivirus: Occasionally, third-party antivirus programs cause trouble. Try disabling yours temporarily, but re-enable it immediately afterward.


While frustrating, the CAA50021 error message in Microsoft Teams is usually rectifiable. By following this guide’s outlined solutions, you should be able to access your Teams account hassle-free once again. If the issue persists, consult Microsoft Support for further help.

author avatar
Derick Payne
My name is Derick Payne. With a deep-seated passion for programming and an unwavering commitment to innovation, I've spent the past 23 years pushing the envelope of what's possible. As the founder of Rizonetech and Rizonesoft, I've had the unique opportunity to channel my love for technology into creating solutions that make a difference.

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