CAA50021 Error: What Is It & How to Fix It in 4 Steps

Re-register your Azure credentials to get rid of the error

by Claire Moraa
Claire Moraa
Claire Moraa
Claire likes to think she's got a knack for solving problems and improving the quality of life for those around her. Driven by the forces of rationality, curiosity,... read more
Reviewed by Alex Serban
Alex Serban
Alex Serban
Windows Server & Networking Expert
After moving away from the corporate work-style, Alex has found rewards in a lifestyle of constant analysis, team coordination and pestering his colleagues. Holding an MCSA Windows Server... read more
Affiliate Disclosure
  • Microsoft Teams is a great collaboration tool but sometimes, you can get the error CAA50021 that prevents you from logging in.
  • Usually, it is because your Office 365 version is due for an update so ensure you get the latest version before you attempt to log in again.

To fix various PC problems, we recommend Restoro PC Repair Tool:
This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues and remove viruses now in 3 easy steps:

  1. Download Restoro PC Repair Tool that comes with Patented Technologies (patent available here).
  2. Click Start Scan to find Windows issues that could be causing PC problems.
  3. Click Repair All to fix issues affecting your computer's security and performance
  • Restoro has been downloaded by 0 readers this month.

Microsoft hosts an umbrella of essential services such as Excel, Outlook, and Microsoft Teams that make working seamless. However, users seem to be having an issue as an error code CAA50021 pops up whenever they try to sign in to the Teams app.

According to the reports, continuously pressing the login button exacerbates the matter and they are hit with a warning that the number of retry attempts exceeds expectations. If this sounds familiar, you’ll want to keep reading the article for a resolution.

Why am I getting the error code CAA50021?

This error can be caused by various reasons, including the following:

  • Office is outdated – The most common cause of this error is that you’re using an older version of Office.
  • Firewall settings – Sometimes, your firewall or antivirus can block certain programs or services if it flags them as a threat to your PC.
  • The device is not connected to Azure – You may be getting this error code because your device is not connected to Azure. If this is the case, look at the status of your device in Azure.
  • Multi-factor authentication – Although multi-factor authentication software adds an extra layer of protection, sometimes verification may fail and lock you out of your account.
  • Expired registration – Devices registered to Azure have a timed license, so if you’re having trouble signing in, your account may have expired.
  • Admin has blocked access – If you’re using a public network, this error may occur if the network administrator has blocked access to Microsoft Teams or other applications.

How can I fix the error code CAA50021?

Check the following before moving on to the advanced troubleshooting:

  • Double-check that you’re using a Microsoft account or a work or school account that is an Office 365 account.
  • Ensure you’re not on a public network or switch to mobile data and see if the error persists. Also, check out how to protect yourself when using public Wi-Fi.
  • Switch from the web version to the app.

1. Update Office

To make sure that you’re getting all of the features available with your subscription, make sure that you’re using the most up-to-date version of Office 365.

You may find that Office keeps asking you to sign in so that you can update to the latest features.

2. Disable antivirus temporarily 

  1. Hit the Start Menu icon, type Windows Security in the search bar, and click Open.
  2. Click on Firewall & network protection then select Public network.
  3. Locate Microsoft Defender Firewall and toggle the off button.Turn off firewall if canon printer driver not installing.

Expert tip:


Some PC issues are hard to tackle, especially when it comes to corrupted repositories or missing Windows files. If you are having troubles fixing an error, your system may be partially broken.
We recommend installing Restoro, a tool that will scan your machine and identify what the fault is.
Click here to download and start repairing.

If you’re using a third-party antivirus program, you should also disable it and try signing back in and check if the error CAA50021 in MS Teams is still there.

  1. Hit the Windows key and select Settings.settings windows 11
  2. Select Accounts on the left pane and tap on Access work or school on the right pane.
  3. Click on Connect next to Add a work or school account.
  4. Now follow the on-screen prompts to connect your device with Azure.

4. Re-register your device with Azure

  1. Hit the Windows key, type cmd in the search bar, and click Run as administrator.
  2. Type and Enter the following command: dsregcmd /leave 
  3. Navigate to the following location and delete the MS-Organization-Access and MS-Organization-P2P-Access entries: Current User\Personal\Certificates
  4. Go back to the Command Prompt window and type the following command: dsregcmd /status
  5. The AzureAdJoined status should read No.
  6. Go back hit the Windows key, type Task Scheduler in the search bar, and click Open.
  7. Navigate to the Task Scheduler Library and select Microsoft.
  8. Select the Windows option and tap on Workplace Join under it.
  9. Launch the Automatic-Device-Join task by right-clicking on it and select Enable.

In case all these fail, your admin IT support should be your next stop. Sometimes, there’s nothing wrong on your end, and it has everything to do with your IT department.

This is especially true for those facing the CAA50021 error on Office 365 products such as OneDrive after multi-factor authentication was enabled. The IT admins will be able to re-register your device or address any other account problems you may be facing.

You may also come across an issue where Microsoft Teams status is stuck on updating so be sure to check out our helpful guide on how to proceed.

If you’d like to try out other collaboration software, especially for small-sized businesses, we have a couple that we can recommend.

Let us know if you have been able to solve this error in the comment section below.

Still having issues? Fix them with this tool:


If the advices above haven't solved your issue, your PC may experience deeper Windows problems. We recommend downloading this PC Repair tool (rated Great on to easily address them. After installation, simply click the Start Scan button and then press on Repair All.

This article covers:Topics: