Microsoft Teams Error Codes: Complete List + Fixes

Microsoft Teams error codes are easier to fix when you sort them by family, not by the last digits on the screen. 0xCAA… codes usually sit around sign-in, token, broker, or policy checks. AADSTS… codes point to Microsoft Entra sign-in policy and account state. Teams Phone SIP codes describe call signaling failures between Teams and the SBC or carrier side. That split matters. A cache reset may help a local loop, while it does almost nothing for a Conditional Access block or a TLS mismatch.

Table Of Contents

Overview Of Microsoft Teams Error Code Families

Not every Teams error means the same layer failed. Some codes come from the local sign-in stack, some from Microsoft Entra policy, and some from Direct Routing SIP signaling. A short taxonomy helps more than a long random list.

Fast Diagnostic Flow

Use the screen where the error appears as your first filter. Desktop-only failures usually point to local app state, while web and desktop failures usually point to account, tenant, or network path. For phone and Rooms scenarios, go straight to the device or SBC logs.

Start
 ├─ Does the error appear before or during sign-in?
 │   ├─ Yes → Check whether Teams on the web works
 │   │   ├─ Web works → Local client state, WAM, cache, BrokerPlugin, WebView2
 │   │   └─ Web fails too → Account, Conditional Access, federation, licensing, service health
 │   └─ No → Move to call, media, or device layer
 ├─ Is the code 0xCAA82EE2, 0xCAA82EE7, 0xCAA7000A, 0xCAA70007, or 0xCAA70004?
 │   └─ Check required endpoints, proxy, firewall, and TLS 1.2
 ├─ Is the code 0xCAA200xx, 0xCAA500xx, or 0xCAA900xx?
 │   └─ Check Conditional Access, Microsoft Entra join state, PRT, UPN, BrokerPlugin
 ├─ Is the device a Teams Rooms system?
 │   └─ Check resource account password, MFA, Conditional Access, proxy authentication, Event ID 1098
 └─ Is the issue a call failure in Teams Phone?
     └─ Read SIP response code, compare Microsoft response code, then inspect SBC logs

Error Codes By Category

Authentication and Sign-In Errors

Microsoft Teams Error Code 0xCAA82EE2 and Microsoft Teams Error Code 0xCAA82EE7

Start with reachability, not reinstallation. These two codes belong high on the list when internet access, required Microsoft 365 endpoints, or the network path between the user and Microsoft is broken. Check whether the issue reproduces on another network, then test the user path with the Microsoft connectivity tools. If Teams calls or meetings also fail, treat UDP 3478–3481 as part of the problem space, not only sign-in.

• What to do first: test the same account in Teams on the web.
• What to inspect next: proxy, firewall, TLS inspection, endpoint allowlists, and split-tunnel VPN design.
• What not to assume: a clean reinstall alone will not fix a blocked endpoint path.

Microsoft Teams Error Code 1001

Microsoft Teams Error Code 1001 often behaves like a broker-side sign-in break, especially when the device also shows Office sign-in friction. Web Account Manager and Microsoft.AAD.BrokerPlugin are the first places to think about. If security software, endpoint filtering, or a proxy blocks the broker process, the user may see blank sign-in windows, stalled authentication, or repeated prompts.

1. Remove stale Microsoft 365 credentials from Credential Manager.
2. Disconnect and reconnect the work account under Access work or school if the device state looks wrong.
3. Reset the app, then clear local Teams cache.
4. Check whether security software is interfering with Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy.

Microsoft Teams Error Code 4c7

Microsoft Teams Error Code 4c7 is worth treating as a sign-in handoff problem first. When the browser path works but the desktop client does not, the gap is often in the local authentication handoff, cached app state, or a federation path that behaves differently in the native client. Clear local Teams state, remove stale work-account traces, and then retest with a fresh desktop sign-in. In federated environments, review the identity path rather than blaming the Teams binary alone.

Microsoft Teams Error Code 2147942402

2147942402 maps to Windows error 0x80070002. That usually means a required local item is missing or cannot be found. In practice, this error often shows up when the local sign-in state, app registration, or cached profile data is damaged. Go in this order: repair the app, reset the app, clear Teams cache, then recheck the device’s work-account registration and broker state.

Microsoft Teams Error Code 0xCAA30194

Microsoft Teams Error Code 0xCAA30194 usually belongs in the “service needed for sign-in is not reachable” bucket. It appears often enough beside other network or identity transport faults that you should test the web client, tenant service health, and endpoint path before spending time on a full rebuild. If multiple Microsoft 365 apps are affected, widen the check to the whole sign-in stack.

Microsoft Teams Error max_reload_exceeded

Microsoft Teams Error max_reload_exceeded usually points to a client reload loop, not a tenant-wide policy failure. Resetting local state works more often than broad tenant changes here. Sign in to Teams on the web first. If the web app works, quit the desktop app fully, clear local cache, remove stale account traces, then reopen the client. If the loop returns after an update, use the app reset path before reinstalling.

Authorization and Token Transport Errors

Microsoft Teams Error Code 0xCAA7000A, Microsoft Teams Error Code 0xCAA70007, and Microsoft Teams Error Code 0xCAA70004

These codes belong to the transport and token-acquisition path. The fix path is usually network first, policy second, and reinstall last. Check whether the device can reach login and Microsoft 365 endpoints without a proxy or TLS break. On older Windows builds, verify that TLS 1.2 is enabled. In managed environments, also check whether Windows network status probing or a locked-down proxy policy is stopping the client from discovering a valid online path.

• Microsoft Teams Error Code 0xCAA7000A: start with timeout-like behavior, token path latency, and blocked endpoints.
• Microsoft Teams Error Code 0xCAA70007: include TLS 1.2, firewall allow rules, proxy settings, and required Windows services in the check.
• Microsoft Teams Error Code 0xCAA70004: use the same sign-in transport path as 0xCAA70007, especially if other Microsoft 365 apps also fail.

Policy, Device Registration, and App State Errors

Microsoft Teams Error Code 0xCAA20002, Microsoft Teams Error Code 0xCAA20003, and Microsoft Teams Error Code 0xCAA20004

Think tenant policy and identity trust when you see this family. Microsoft Teams Error Code 0xCAA20003 maps well to a case where the SAML token from the on-premises identity provider is not accepted by Microsoft Entra ID. Microsoft Teams Error Code 0xCAA20004 is the clearer Conditional Access member of the group. Microsoft Teams Error Code 0xCAA20002 should be approached the same way first: verify tenant, account, license, device registration, and policy evaluation before touching the local app.

• Check Conditional Access: compliant device, approved app, known location, and session control requirements.
• Check federation: if you use AD FS or another identity provider, review sign-in and trust logs there.
• Check device join: run dsregcmd /status and confirm the device is in the expected join state.
• Check time: token and federation flows are sensitive to clock drift.

Microsoft Teams Error Code 0xCAA50021, Microsoft Teams Error Code 0xCAA50024, and Microsoft Teams Error Code 0xCAA5001C

This family tends to live around broker state, account registration, licensing, and device management steps. Microsoft Teams Error Code 0xCAA50021 is a strong signal to inspect BrokerPlugin, stale credentials, activation state, and Microsoft Entra device registration. Microsoft Teams Error Code 0xCAA50024 is often worth checking against MDM or Terms Of Use style policy flow, especially if the account can sign in elsewhere but gets pushed into a policy step it cannot complete in the current path. Microsoft Teams Error Code 0xCAA5001C fits the same repair lane: token broker, account state, and device join.

1. Remove stale MicrosoftOffice16 entries from Credential Manager.
2. Confirm the user has the correct license.
3. Check whether users may register and join devices in Microsoft Entra ID.
4. Review BrokerPlugin and local TokenBroker data only after the account and policy layer looks clean.
5. Rejoin the device to Microsoft Entra ID if the join state is wrong.

MFA, Token Renewal, and Federation Errors

Microsoft Teams Error Code 0xCAA90014, Microsoft Teams Error Code 0xCAA90018, Microsoft Teams Error Code 0xCAA90056, and Microsoft Teams Error Code 0xCAA90057

This family is about federation, realm discovery, or refresh-token health. Microsoft Teams Error Code 0xCAA90014 is the clearest one: the WS-Trust response reported a fault and the client failed to get an assertion. That pushes you to Federation Server settings, WS-Trust path, and authentication logs. Microsoft Teams Error Code 0xCAA90018 deserves a check of UPN format, custom domain, and realm discovery. Microsoft Teams Error Code 0xCAA90056 and Microsoft Teams Error Code 0xCAA90057 fit the PRT and token-refresh lane: device sign-in state, cached token age, and silent refresh health.

Use dsregcmd /status here. If the AzureAdPrt field is NO, or the AzureAdPrtUpdateTime is stale, stop guessing and investigate the device registration and refresh path. On Microsoft Entra joined or hybrid joined devices, the primary refresh token is the desktop sign-in anchor. If it cannot refresh, users drift into repeated prompts and odd Teams sign-in failures.

• For 0xCAA90014: inspect federation and WS-Trust logs, not only Teams logs.
• For 0xCAA90018: verify the user’s UPN suffix, tenant custom domain, and alternate login design if you use a non-routable on-prem domain.
• For 0xCAA90056 and 0xCAA90057: check PRT status, re-evaluate device join, then force a clean reauthentication path.

Microsoft Teams Rooms Resource Account Errors

Microsoft Teams Rooms Error Code AADSTS50055, Microsoft Teams Rooms Error Code AADSTS50076, Microsoft Teams Rooms Error Code AADSTS50079, Microsoft Teams Rooms Error Code AADSTS50126, and Microsoft Teams Rooms Error Code AADSTS53003

Microsoft Teams Rooms has its own sign-in rules. User-interactive MFA is not supported for resource accounts, and proxy authentication is not supported on Teams Rooms. That changes the fix path immediately. Microsoft Teams Rooms Error Code AADSTS50076 and Microsoft Teams Rooms Error Code AADSTS50079 usually mean the resource account is being pushed into MFA or registration steps that a room device cannot complete. Microsoft Teams Rooms Error Code AADSTS53003 means token issuance is being blocked by Conditional Access. Microsoft Teams Rooms Error Code AADSTS50126 points to invalid username or password. Microsoft Teams Rooms Error Code AADSTS50055 is the expired-password member of the set.

• Password checks: confirm the resource account password is current and not expired.
• MFA checks: exclude resource accounts from interactive MFA and registration prompts.
• Conditional Access checks: use a separate device-focused policy built for Teams Rooms.
• Network checks: allow standard Microsoft 365 endpoints and remove proxy authentication from the path.
• Log checks: inspect Event Viewer and the Microsoft Entra operational logs; Event ID 1098 is especially useful in room sign-in work.

Microsoft Teams Phone SIP Response Codes

For Teams Phone, read SIP codes as signaling outcomes. The SIP response code tells you what happened in the call setup path. The Microsoft response code tells you whether the last failure came from Microsoft or from the SBC. If the Microsoft response code starts with 560, use the last three digits as the final SBC-side SIP result and start with SBC logs. If not, start with the Microsoft-side path and the Teams admin center.

Do not skip the transport layer. Many repeated 4xx patterns grow out of TLS 1.2 problems, certificate chain issues, FQDN mismatch, or an SBC sending SIP options to stale IPs instead of the Microsoft SIP proxy FQDNs. In Direct Routing, Record-Route, Contact, CN/SAN match, and the full certificate chain matter more than people expect.

Universal Troubleshooting Checklist

1. Check Microsoft 365 Service Health before changing local settings. A tenant-side issue can mimic a broken desktop client.
2. Test Teams on the web. This is the fastest split between local client trouble and account or policy trouble.
3. Check the Teams client version. Teams updates automatically and should stay current.
4. Confirm required network ports: TCP 80/443 and UDP 3478, 3479, 3480, 3481.
5. Clear local Teams cache on supported desktops after fully quitting the app.
6. Review work account state under Access work or school.
7. Run dsregcmd /status on managed Windows devices and read the join and PRT fields.
8. Check system time. Small time drift can break token and federation flows.
9. Inspect Credential Manager for stale MicrosoftOffice16 entries.
10. Review Conditional Access and device compliance only after you know whether the web client succeeds.

Preventive Practices That Reduce Recurrence

Keep Teams current. The desktop client updates on its own schedule, and older builds drift into avoidable sign-in and reliability issues. Teams checks for updates regularly and rolls them out in waves. For organizations that also manage Microsoft 365 Apps carefully, use Current Channel for pilot users and Monthly Enterprise Channel for broad managed deployment of companion apps. Teams itself should still stay current on its own servicing path.

Use policy design that matches the device type. Interactive MFA belongs on user sessions, not on Teams Rooms resource accounts. Compliant device checks work better when the device is enrolled and the policy is meant for that class of device. Reusing one policy set for laptops, phones, shared devices, and rooms usually creates noise.

Monitor trend data instead of waiting for tickets. The Teams client health dashboard helps admins watch crashes, launch failures, update failures, affected users, and impacted devices over the last 7 and 28 days. A small jump in launch failures often shows up there before the helpdesk mailbox gets busy.

For Teams Phone, treat certificate work as scheduled maintenance. Keep a calendar for SBC certificate renewal, validate the full chain, and confirm that CN and SAN still match the production FQDN. After renewal, close old TLS sessions cleanly so the new certificate is the one actually in use.

FAQ