Microsoft Teams Error CAA70004 — Sign-In and Authentication Loop

Fix Microsoft Teams desktop error code CAA70004 causing sign-in failures, authentication loops, and inability to access Teams on Windows. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: Error CAA70004 is a Teams desktop authentication error preventing successful sign-in. The error creates a loop where Teams repeatedly asks for credentials but never completes sign-in. This typically affects the Teams desktop app, not the web version in the browser. The issue is often related to cached credentials, proxy settings, or conditional access policies. Multiple Microsoft 365 accounts on the same machine can trigger this error. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: Corrupted Teams cache or credential store causing authentication to fail. Network proxy or VPN interfering with Microsoft 365 authentication endpoints. Conditional access policy requiring device compliance that the machine does not meet. Multiple Microsoft 365 accounts creating credential conflicts in the credential manager. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Clear Teams cache: close Teams, delete contents of %appdata%\Microsoft\Teams, restart Teams. Clear Windows credentials: Credential Manager > Windows Credentials > remove all Microsoft/Teams entries. Disable proxy temporarily: Settings > Network & Internet > Proxy > turn off manual proxy setup. Try signing in via Teams web (teams.microsoft.com) to verify credentials work. Reinstall Teams: uninstall completely, delete %appdata%\Microsoft\Teams folder, reinstall from teams.microsoft.com. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

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