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0xCAA20003

Microsoft 365 0xCAA20003 in Teams: authorization problem at sign-in

Verified with sources3 sourcesReviewed Oct 3, 2026
Technician coming? See the 3 steps they must show you

Risk level

Medium

Proceed carefully and stop if the check is unclear.

Urgency

Medium

Quick answer

Teams will not let you in and shows 0xCAA20003, an authorization problem. First check the device date and time are correct: if they are wrong, it cannot connect to secure (https) sites.

Safety first

Stop and check this first

  • On a device your organisation manages, time may be synced by policy: if you cannot change it, do not force settings and tell IT.

Safe checks you can perform

  • Device date and time
  • Teams client update
  • Reinstall Teams
  • Report the code to IT support

Leave these tasks to a qualified professional

  • Do not attempt this professional task: Teams Sign-in diagnostic
  • Do not attempt this professional task: Microsoft Entra sign-in logs
  • Do not attempt this professional task: Support request with logs

What a technician must be able to justify

Technician visit

These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.

These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.

  1. Teams Sign-in diagnostic

    What they doThe Microsoft 365 administrator runs the Teams Sign-in diagnostic in the admin center with the user's email, or the Teams Sign in test in the Microsoft Remote Connectivity Analyzer.

    They must show youthe test results.

    In writingthe issue found and the fix applied.

  2. Microsoft Entra sign-in logs

    What they doThe administrator reviews the user's attempts at the time of the error in the Microsoft Entra admin center, Monitoring & health, Sign-in logs.

    They must show youthe failed attempt entry.

    In writingthe failure reason and the change made.

  3. Support request with logs

    What they doIf nothing works, the administrator collects Teams debug logs and opens a support request with the code from the sign-in screen.

    They must show youthe request number.

    In writingthe logs sent and Microsoft's reply.

Before accepting a part or repair

Nothing has been shown yet. Do not accept a part swap based on the code alone.

Follow these steps

Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.

  1. Device date and time

    No special tools

    Who:
    you.
    How:
    open the system date and time settings (Windows or Mac) and check the date and time match the real ones.
    Result that matters:
    whether the time was wrong and fixing it lets you into Teams.
    If you get in:
    the time offset blocked the secure connection.
    If the time was already right or it still fails:
    update Teams.
    Evidence to keep:
    screenshot of the time before and after.

    Evidence: Why am I having trouble signing in to Microsoft Teams?

  2. Teams client update

    No special tools

    Who:
    you.
    How:
    in Teams, open the Settings and more menu next to your profile picture at the top right and select Check for updates. Install anything offered and sign in again.
    Result that matters:
    whether 0xCAA20003 goes away on the latest version.
    If you get in:
    the client was missing the latest update.
    If it repeats:
    go to the next check.
    Evidence to keep:
    Teams version before and after.

    Evidence: Fix Teams sign-in errors

  3. Reinstall Teams

    No special tools

    Who:
    you, or IT support on a managed device.
    How:
    uninstall Teams, open %appdata%\Microsoft, delete the Teams folder, download Teams again and install it. If you can, right-click the installer and Run as administrator.
    Result that matters:
    whether the error persists on a clean install.
    If you get in:
    the local install was damaged.
    If it persists:
    the cause is in the account, network or tenant; hand it to IT support.
    Evidence to keep:
    date of the reinstall and the code shown afterwards.

    Evidence: Fix Teams sign-in errors

  4. Report the code to IT support

    No special tools

    Who:
    you.
    How:
    note the status code at the bottom left of the window (0xCAA20003), the time and whether other Office apps fail too, and send it to your IT admin.
    Result that matters:
    IT getting the exact code.
    If IT finds the cause in the tenant or network:
    they fix it on their side.
    If not:
    IT opens a support request with Microsoft including debug logs.
    Evidence to keep:
    screenshot of the sign-in screen with the code.

    Evidence: Fix Teams sign-in errors · Why am I having trouble signing in to Microsoft Teams?

Still not solved

If the error persists, stop here. See what the technician must do and show you.

Where this code applies

A code is meaningful only inside the right product and version context.

Primary scope

System
Software and digital services
Brand
Microsoft 365
Product type
Office suites

Known code variants

  • CAA20003
  • código de estado 0xCAA20003
  • Teams 0xCAA20003

What it means

Microsoft describes 0xCAA20003 as an authorization problem during Teams sign-in. The action it documents is to check the device date and time, because a wrong time prevents the secure (https) connection to the service. The code does not say whether the offset comes from the clock, the time zone or another authorization failure; if the time is right, diagnosis moves to your IT admin.

Warnings and stop conditions

  • Loweditorial warning

    On a device your organisation manages, time may be synced by policy: if you cannot change it, do not force settings and tell IT.

    Evidence: Why am I having trouble signing in to Microsoft Teams?

Symptoms and causes

Probable causes · in order

  • Wrong device date or timeCommon

    This is the cause Microsoft ties to the code. Confirmed if fixing the time lets sign-in work.

    Evidence: Why am I having trouble signing in to Microsoft Teams?

  • Another authorization problem in the account or tenantPossible

    The time is right and the error stays. Only the admin sees it in the Teams diagnostic or the sign-in logs.

    Evidence: Fix Teams sign-in errors · Why am I having trouble signing in to Microsoft Teams?

Virtual technician

Does 0xCAA20003 still appear after these checks?

Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.

Start diagnosis

Sources and technical references

  1. 1

    Fix Teams sign-in errors

    Microsoft · 2025 · official_doc

  2. 2

    Why am I having trouble signing in to Microsoft Teams?

    Microsoft · 2026 · official_doc

  3. 3

    What are Microsoft Entra sign-in logs?

    Microsoft · 2026 · official_doc

Sources: Fix Teams sign-in errors · Why am I having trouble signing in to Microsoft Teams? · What are Microsoft Entra sign-in logs?reviewed 2026-10-03 · verified

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