Some of the users reported that they are not able to sign in to Microsoft Teams and see Error CAA5004B. This error is similar to the one you may see in Microsoft Outlook. In this article, we are going to find the solutions to fix this Microsoft Teams Error CAA5004B.

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We couldn’t sign you in. If this error persists, contact your system administrator and provide the error code CAA5004B.

Fix Microsoft Teams Error CAA5004B

If you see Microsoft Teams Error CAA5004B when you try to sign in, follow the solutions mentioned below to resolve the issue:

1. Switch off VPN, Antivirus, and Firewall
2. Make a new MS Teams password
3. Reconnect your MS Teams account in Windows
4. Clear cache files
5. Join the group again or ask the admin to re-invite you again
6. Reinstall MS Teams

Let’s get started.

1] Switch off VPN, Antivirus, and Firewall

It is important to make sure that your VPN is turned off and that neither your Firewall nor the antivirus software is preventing the app from operating properly. VPN is considered the best tool when it comes to surfing online anonymously, however, enabling it tends to create confusion and later in such kind of error messages. And sometimes, antivirus software and Firewall detect app files and block them thus resulting in error codes.

2] Make a new MS Teams password

If you are not able to log in and access the organization and have already logged out and then log in again yet no progress then change your MS Teams password. Changing the password will add your account as an authorized one in the MS Teams database. Now, log in with your new password and see if the issue persists.

3] Reconnect your MS Teams account in Windows

The error may trouble you if MS Teams is not included in the Windows Account Manager. The primary reason behind this is that MS Teams sync the account details from the Windows account manager but due to no information there, MS Teams deems your account as an unauthorized login attempt. To resolve the issue, follow the steps prescribed below to reconnect your MS Teams account in Windows:

1. Click Win + I to open Settings.
2. Go to Accounts and click on Access work or school.
3. Find the account you are using for Teams and disconnect it.
4. After 30 seconds, reconnect it and manually add the account if it is not listed under Work or School.

Make sure to delete the cache and then relaunch MS Teams and check the issue.

4] Clear cache files

You might encounter the issue if the cache files of MS Teams are faulty. Deleting cache files will not only replace the corrupted ones but also wipe out log-in data, thereby offering you a clean slate for a new log-in process. Here’s how you can do the same:

Launch MS Teams and see if you are able to log in or not.

5] Join the group again or ask the admin to re-invite you again

If deleting the cache files did not go as we planned then either leave the group and rejoin or ask the group admin to remove you and then reinvite you to the group. Once the admin reinvites you, try logging in, and see if the issue is resolved or not.

6] Reinstall MS Teams

If nothing worked, your last resort is to reinstall the MS Teams completely and then do a fresh installation of the same. A fresh installation will allow the app to install every single missing file if any, and they will be not corrupted. To do the same, follow the prescribed steps.

1. Open Settings.
2. Go to Apps > Installed apps or Apps & features.
3. Look for MS Teams.
   > Windows 11: Click on the three vertical dots and select Uninstall.
   > Windows 10: Click on the app and select Uninstall.
4. And again click on the Uninstall button to confirm your actions.
5. Now, go to its website and reinstall it.

Hopefully, this will do the job.

Read: Fix Microsoft Teams Sign-in Error Codes and Problems.