Microsoft Teams error 0xCAA70004: a sign-in failure, not a Teams fault

The codes Microsoft actually documents

Teams sign-in codes look interchangeable and are not. Microsoft's troubleshooting article names a specific set and gives each a different cause, so the first useful step is reading the exact code on the sign-in screen rather than searching for the general symptom.

0xCAA82EE7 and 0xCAA82EE2 are network problems: Microsoft's instruction is to make sure the user has internet access, then to use the Network assessment tool to verify that the network and the elements between the user and the Microsoft network are configured correctly, so that Teams can reach the required IP addresses and ports.

0xCAA20004 is different in kind — Microsoft states it occurs when an issue affects conditional access, which is a tenant policy question rather than anything on the machine.

0xCAA70004 and 0xCAA70007 come with a diagnostic hint attached, and it is the most useful sentence in the article: Microsoft groups them with the case where the sign-in issue also occurs in other Office applications, pointing at guidance about connection issues after an Office 2016 build update. If Outlook and Word are failing to sign in too, Teams is a symptom rather than the cause.

The two diagnostics before the manual work

Microsoft offers automated checks that are worth running before touching the client. The Teams Sign-in diagnostic runs from the Microsoft 365 admin centre: enter the affected user's email address and run the tests. It needs an administrator account, and Microsoft notes it is not available for Microsoft 365 Government, Microsoft 365 operated by 21Vianet, or Microsoft 365 Germany.

For anyone without admin access there is the Microsoft Remote Connectivity Analyzer. Open the Teams Sign in test, sign in with the account you want to test, enter the verification code and select Verify. Microsoft describes it as verifying that the user account meets the requirements to sign in to Teams — which is exactly the question you want answered before reinstalling anything.

The Remote Connectivity Analyzer does not support Microsoft 365 Government environments, GCC or GCC High, so on those tenants the admin diagnostic is the route.

The manual sequence

If the diagnostics find nothing, Microsoft's first manual step is to check the client is current: open the Settings and more menu next to the profile picture at the top right of the Teams window and choose Check for updates. The desktop app is meant to update itself, but Microsoft explicitly covers the case where it has not.

Then read the code and follow the guidance for that specific member of the family. Microsoft's article is clear that if the code is not listed, the general sign-in troubleshooting page is the next stop rather than the code-specific advice.

There is one case worth separating out: if the sign-in error happens only in the Teams web client, Microsoft points at its article on Teams being stuck in a login loop, which has browser-specific resolutions. A failure that occurs only in a browser is not the same problem as one in the desktop app.

Reinstalling, and the folder that has to go

Microsoft's last step before a support request is a reinstall, and the middle part is the part people skip. Uninstall Teams, then browse to the %appdata%\Microsoft folder and delete the Teams folder, then download and install Teams again — as an administrator if possible, by right-clicking the installer and selecting Run as administrator.

Deleting that folder is what makes it a reinstall rather than a reinstallation of the same broken state. It holds the cached profile and credentials, so an uninstall and reinstall that leaves it in place frequently reproduces the identical error within seconds of signing in.

If none of this resolves it, Microsoft's instruction is to create a support request, collect debug logs, and provide the error code displayed on the Teams sign-in screen. The code is the thing support will ask for first, so note it before the window closes.

Sources and review notes

Checked on September 8, 2026. Based on Microsoft's Learn article on fixing Teams sign-in errors. The codes named here — 0xCAA82EE7, 0xCAA82EE2, 0xCAA20004, 0xCAA70004 and 0xCAA70007 — are the ones that article documents. Other codes circulate widely (caa5004b, caa20002, caa30194) but appear only in Microsoft Q&A threads rather than documentation, so they are deliberately not explained here. The framing of the other-Office-apps check as the key diagnostic is editorial. Glitchary is independent of Microsoft.

• Microsoft: fix Teams sign-in errors