If you are trying to sign in to Microsoft Teams on your Windows 10 or 11 computer but keep getting the following sign-in error code CAA50021. This article will guide you through several different troubleshooting steps you can take to resolve the issue. Alternatively, you can sign into Microsoft Teams from the web if you’re pressed for time.


  1. The steps for fixing Microsoft Teams Cache to fix sign-in error CAA50021
  2. What causes Microsoft Teams sign-in error CAA50021? Quite a few different scenarios.

Clear your Microsoft Teams Cache to fix sign-in error CAA50021

The first, easiest and quickest thing you can do to fix Microsoft Teams Error CAA50021 is to restart your Internet router/modem, and then restart your computer. This will usually fix Microsoft Teams sign-in issues but if it doesn’t, you can clear your Microsoft Teams Cache. To clear your Microsoft Teams cache on Windows 10 you’ll need to do the following.

  • Open the Run tool by pressing Windows Key + R.

  • Next copy and paste %appdata%\Microsoft\teams\Cache into the text box and press Enter. This will open a File Explorer window in the exact location of one of Teams caches. Press Ctrl+A to select everything within the location then press Delete to delete it all. Once you have deleted everything do the same for all of the following locations:

%appdata%\Microsoft\teams\application cache\cache





%appdata%\Microsoft\teams\Local Storage


How to fix Microsoft Teams error CAA50021 on Windows 11

After you have cleared all of the above, you can restart your computer and sign back into your Microsoft Teams account. It should be working normally.

Release and Renew the IP address to fix Teams error code CAA50021.

  • To do this type CMD into the Start menu.

  • Once Command Prompt pops up, select Run as administrator on the right.

  • Now in the command windows type ipconfig/ release then press the Enter. This command will release the IP Address of your computer.

  • Then type ipconfig/ renew and press the Enter. This will renew the IP address of your computer.

After the commands run, close the window and Restart your computer. After a restart sign back in and Microsoft Teams should be working.

What is causing Microsoft Teams Error CAA50021 on Windows 11?

While there are a lot of different reasons that may be causing the problem in Microsoft Teams no one really knows what the exact cause of the problem is. Sometimes a simple system restart will solve the problem while other times it takes a full cache clean or a reinstallation. Thankfully, there are quite a few different troubleshooting steps you can take to resolve this issue. There’s also the web version which you can use if you need immediate access to Microsoft Teams and don’t have time to jump through troubleshooting hoops. If you also get stuck trying to sign into teams or can't change your email address check out this guide as well.

How to fix Microsoft Teams can’t change sign-in email address.