All fixes for error caa70004 in Microsoft Teams

A number of my customers experience error code caa70004 when they try to start the Microsoft Teams desktop app. The exact error message reads:

Error code – caa70004
There’s a more permanent way to sign in to Microsoft Teams. If you’re having trouble completing the process, talk to your IT admin.

I have spent a lot of time troubleshooting and resolving this caa70004 error. Causes can be very diverse: network issues (firewall, vpn), caching issues (after changing a password), or computer settings (disabled TLS, compatibility, permissions). Below I have listed all the solutions, starting with the most likely and easiest solution. Try to start Microsoft Teams after each fix. If it is not resolved, continue with the next possible fix.

Fix 1: Run Microsoft Teams once as an administrator

Sometimes, Microsoft Teams needs to make some modifications to your system, before running correctly. To run Teams as administrator:

1. Right-click Microsoft Teams
2. Select Run as administrator
   
3. Logon to Teams with an Office 365 account. Once logged on successfully, sign out and restart Microsoft Teams as usual

Fix 2: Run Teams in Compatibility Mode

Some users have been successful by running Teams in compatibility mode. Follow these steps to set Teams’ compatibility mode to Windows 8:

1. In the Windows 10 start menu, right-click the Microsoft Teams shortcut and select Open file location
   
2. File Explorer opens to the shortcut path. Probably something like C:\Users\%username%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs
   Right-click the Microsoft Teams shortcut and select Properties
3. In the Properties window, select the Compatibility tab. Enable the Run this program in Compatibility Mode for checkbox and select Windows 8
   
4. Click OK to save the changes. Next, try to run Microsoft Teams from the Windows 10 start menu to verify error caa70004 is fixed/

Fix 3: Enable TLS in Internet Options

In a rare case, I had a client whose TLS was disabled in Internet Options (!). To verify TLS settings and possibly enable TLS, follow these steps:

1. From the Windows 10 start menu, start typing Internet Options. Open Internet options
   
2. Select the Advanced tab and scroll down to the Security section.
3. Check to see if you have TLS 1.1 enabled, TLS 1.2 enabled (checked).  If not, check the box to enable it.
   
4. Select OK to save the changes.
5. Try to run Microsoft Teams

Fix 4: Disconnect VPN

In case you’re using a VPN connection, make sure to disconnect it. Some VPN and/or firewall configurations block or tamper traffic which may lead to error caa70004 while signing in. Once you are logged on to Teams, it’s ‘safe’ to (re)connect the VPN connection.

It is not viable to list all possible VPN solutions here. Please leave a comment if you are having trouble turning off your VPN connection or firewall, or if you’re running into any issues.

Fix 5: Clear cache of Microsoft Teams

The cache files of Microsoft Teams may very well cause the caa70004 error, especially if you recently changed your password. Clearing the Teams cache is necessary to delete any outdated data:

1. Make sure Teams is not running. Check your system tray (at the right bottom on your taskbar) too, as Teams also runs minimized. If it is running, right-click the Teams icon and select Quit
   
2. Open File Explorer and go to
   %AppData%\Microsoft\teams\cache
   This will take you to a folder like
   C:\Users\%yourname%\AppData\Roaming\Microsoft\teams\cache
3. Delete all files from this folder
4. Try to start Microsoft Teams to see if error caa70004 is fixed.

Fix 6: Enable Forms-based Authentication and WS-Trust in your ADFS

This solution is very specific and intended for system administrators. But in case all users in a company have sign-in issues, this setting must not be overlooked:

https://social.technet.microsoft.com/wiki/contents/articles/51619.microsoft-teams-login-error-modern-authentication-failed-here-status-code-caa20004.aspx

Workaround for caa70004 error in Teams

If nothing seems to work for now, your best workaround is to use the web version of Microsoft Teams. The web version works surprisingly well. And as a bonus, you’re able to run Teams for multiple tenants. For example, I often need to be online for customer A and customer B. To avoid collaboration issues, I prefer to have dedicated accounts in the customers’ tenant.

Open Microsoft Teams web version from here: https://teams.microsoft.com

If you’re still experiencing problems with Microsoft Teams and error caa70004, please leave a comment! This website is visited thousands of times a day. There is a good chance that I or someone else has an answer to your question.

If I helped you out with this post, please leave a comment too with your experiences! I’d love to read them! And while you’re here, why not take a look at how to improve your Microsoft Teams performance? Microsoft Teams tend to become very sluggish after some weeks with high cpu and memory usage.