Fixes / Teams · Checked September 30, 2026

Teams error code caa70004: what it means and how to fix it

Short answer

Teams error code caa70004 (0xCAA70004) means Teams on Windows couldn't reach Microsoft's sign-in service. Microsoft says the usual cause is a misconfigured proxy or a network-inspection program such as Fiddler. Disconnect from any VPN, turn off manual proxy settings and quit Fiddler or similar tools, then sign in again. If that doesn't work, reset Teams in Windows Settings.

What this message means

Teams on Windows doesn't handle your password itself. It asks a Windows component called Web Account Manager (WAM, which runs as Microsoft.AAD.BrokerPlugin.exe) to get a sign-in token from login.microsoftonline.com. Error 0xCAA70004 means that request couldn't reach the server. Microsoft describes it as "the server or proxy wasn't found". Your internet connection usually works fine for everything else. The problem is the specific path the sign-in broker takes, which a proxy, VPN, firewall, antivirus program, outdated TLS setting or corrupted local sign-in data can block. Outlook, OneDrive or other Office apps often fail in the same way.

Common causes

Cause	How to tell
A misconfigured proxy or a traffic-inspection tool (Fiddler, Charles, some web filters)	The error appears on the office network or with a proxy set in Windows, but not on a home or mobile hotspot connection. Or you have Fiddler or a similar debugging proxy running.
A VPN or corporate network routing the sign-in traffic badly	Teams signs in fine as soon as you disconnect the VPN, and fails again when you reconnect.
A firewall or antivirus blocking the Windows sign-in broker	Websites open normally, but Teams, Outlook and OneDrive all fail to sign in. In Event Viewer under Applications and Services Logs > Microsoft > Windows > AAD > Operational, you see errors with codes like 0xCAA7xxxx or 0xCAA8xxxx next to XMLHTTPWebRequest.
TLS 1.2 disabled in Windows Internet Options	In Internet Options > Advanced, the "Use TLS 1.2" box is unchecked. This is common on PCs that have been through old security tweaks or hardening scripts.
Corrupted Teams cache or stale Windows sign-in data	The error started after an update, a password change or a crash. Teams on the web (teams.microsoft.com) works in the same browser on the same network.
An outdated Teams client	You are still on classic Teams, or the "Check for updates" option offers a new version.

How to fix it

1. Take the proxy, VPN and inspection tools out of the path

Windows 10 and Windows 11

Quit Teams fully: right-click the Teams icon in the taskbar's notification area and select Quit.
Disconnect from any VPN and close Fiddler, Charles or any other debugging proxy.
Open Settings > Network & internet > Proxy. Turn off "Use a proxy server" under Manual proxy setup, unless your IT department requires it.
If you manage the PC, open Command Prompt as administrator and run: netsh winhttp show proxy. If it lists a proxy you don't need, run: netsh winhttp reset proxy.
If you can, switch to a different network (for example, a phone hotspot) to rule out the office network.
Start Teams and sign in again.

2. Turn on TLS 1.2 and reset Internet Options

Windows 10 and Windows 11

Quit Teams and any other Office apps.
Press Windows logo key + R, type inetcpl.cpl and press Enter to open Internet Properties.
On the Advanced tab, scroll to the Security section and make sure "Use TLS 1.2" is checked (also check "Use TLS 1.3" if it's listed). Select Apply.
If the error continues, select Reset on the same tab, check "Delete personal settings", then select Reset and Close. Several users on Microsoft Q&A report this was the only fix that worked for them.
Start Teams and sign in.

3. Reset the Teams app (clears its cache)

New Teams on Windows 10 and Windows 11. For classic Teams, delete the contents of %appdata%\Microsoft\Teams instead.

Quit Teams: right-click the Teams icon on the taskbar and select Quit.
Open Settings > Apps > Installed apps and type Microsoft Teams in the search box.
Select the More options button (...) next to Microsoft Teams, then select Advanced options.
Under Reset, select Reset. This removes local Teams data and your personalization settings, but not your chats.
Alternatively, press Windows logo key + R, open %userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams and delete everything in that folder.
Restart Teams and sign in.

4. Reconnect your work or school account in Windows

Windows 10 and Windows 11 (work or school Microsoft 365 accounts)

Open Settings > Accounts > Access work or school.
If your work account is listed but sign-in keeps failing, select it and choose Disconnect. Skip this if your IT department manages the PC as Entra-joined.
Select Connect and sign in with your Microsoft 365 work email and password.
Restart the PC, then open Teams. Admins on Microsoft Q&A report this fixed caa70004 for all of their affected users.

5. Allow the Windows sign-in broker through your firewall and antivirus

Windows 10 and Windows 11, usually needs an administrator

Open Microsoft Edge in InPrivate mode and go to https://login.microsoftonline.com. If the page fails to load, the network, firewall or antivirus is blocking sign-in.
In your firewall or antivirus, allow C:\Windows\SystemApps\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\Microsoft.AAD.BrokerPlugin.exe.
Also allow C:\Windows\System32\backgroundTaskHost.exe.
Make sure the network doesn't block login.microsoftonline.com or other Microsoft 365 endpoints.
Restart Teams and sign in.

6. Update or reinstall Teams

If Teams opens, select Settings and more (...) next to your profile picture, then select Check for updates.
If it still fails, uninstall Teams from Settings > Apps > Installed apps.
Download Teams again from microsoft.com/microsoft-teams/download-app and install it. If possible, right-click the installer and choose Run as administrator.
Sign in again. If you need Teams immediately, use teams.microsoft.com in your browser in the meantime.

Next time, skip the search

Crade is an AI assistant for Mac and Windows that sees your screen. When a message like this pops up, ask “what does this mean?” and it explains the exact error in front of you, step by step.

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Still not fixed?

Use Teams on the web at teams.microsoft.com so you can keep working. Then send your IT admin the full code (0xCAA70004) and the time the error happened. An admin can run the Teams Sign-in diagnostic in the Microsoft 365 admin center or the Teams Sign in test in Microsoft Remote Connectivity Analyzer (testconnectivity.microsoft.com). They can also check the AAD Operational log in Event Viewer for the blocked request. If you're on a personal PC with no IT department, run the Microsoft 365 Sign-in troubleshooter (aka.ms/SaRA-OfficeSignIn-sarahome) before contacting Microsoft Support.

Questions people ask

Is caa70004 a problem with my internet connection?

Usually not. Your internet works, but the specific connection Teams uses to reach login.microsoftonline.com is blocked or redirected, most often by a proxy, VPN, firewall or antivirus.

Why does Teams work in the browser but not in the desktop app?

The browser signs in on its own, while the desktop app goes through the Windows Web Account Manager broker. If the broker is blocked or its data is corrupted, only the desktop app fails.

What is the difference between caa70004 and caa70007?

Both are network errors during sign-in. Microsoft says 0xCAA70004 means the server or proxy wasn't found, and 0xCAA70007 means the sign-in service couldn't be reached. The same fixes apply to both.

Will clearing the Teams cache delete my chats or files?

No. Chats, files and meetings are stored in Microsoft 365, not on your PC. Resetting Teams only removes local data such as cached files and personalization settings.

Does error caa70004 happen on Mac?

The code comes from the Windows sign-in broker, so almost all reports are from Windows 10 and 11. If Teams on a Mac won't sign in, the proxy and VPN checks still apply, but the Windows-specific fixes don't.

Sources

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