caa20003
Microsoft Teams Software
Severity: MinorWhat Does This Error Mean?
Teams error caa20003 appears at sign-in when Azure AD rejects the authorization request — almost always because the cached credentials on your PC do not match the account you are typing.
This happens after password changes, after switching tenants, or when an old Office sign-in is still cached.
The fix is to clear the Microsoft account cache, then sign in fresh.
Affected Models
- Microsoft Teams desktop on Windows 10 and 11
- Microsoft Teams desktop on macOS
- Teams 'classic' (deprecated) and the new Teams 2.0
- Teams for school and work accounts (not personal Skype/Live accounts)
Common Causes
- Old account cached from a previous Office or Teams sign-in
- Password was changed but the cache still holds the old token
- The account was moved between tenants
- MFA prompt was missed and the token expired
- Time on the PC is wrong — Kerberos and OAuth both reject signed tokens with skewed clocks
How to Fix It
-
Sign out of Teams completely.
Click your profile picture top-right and choose Sign out.
Then quit Teams from the system tray — right-click the Teams icon near the clock and pick Quit.
If Teams refuses to close, end the process from Task Manager (look for Teams.exe and ms-teams.exe). -
Remove the cached account from Windows.
Open Settings → Accounts → Access work or school.
Find the account that matches the email failing to sign in.
Click it and choose Disconnect.
Confirm the prompt.
This clears the WAM token cache that Teams reuses. -
Clear the Teams cache folder.
Quit Teams.
Open Run (Win+R) and paste %appdata%\Microsoft\Teams (classic Teams) or %localappdata%\Packages\MSTeams_8wekyb3d8bbwe (new Teams).
Delete everything inside the Cache and Code Cache subfolders.
Do not delete the parent folders themselves. -
Check the system clock.
Right-click the clock and choose Adjust date/time.
Make sure 'Set time automatically' is on.
If the time is more than five minutes off, sign-in tokens fail with caa20003.
Click Sync now to force a sync. -
Sign in again and watch the prompt.
Reopen Teams.
Type the email address carefully — caa20003 also fires when the entered domain does not match the licensed tenant.
If you have multiple Microsoft accounts, pick the one your IT admin assigned for Teams, not your personal Outlook.com account.
Frequently Asked Questions
Will deleting the Teams cache lose my chats or files?
No.
Chats, channels, and files live on Microsoft's servers — the local cache is just a copy.
When you sign in again Teams downloads what it needs.
The first launch after a cache clear is slower than usual; that is normal.
Why does caa20003 only happen on the desktop app, not in the browser?
The browser uses a fresh login each time and does not pull from the Windows Account Manager cache.
Desktop Teams shares the cache with Office and Edge — so a stale token in any of those can break Teams sign-in while leaving teams.microsoft.com in a browser working fine.