Troubleshoot Microsoft 365 and Entra Sign-In Errors
Microsoft 365 sign-in and authentication failures often appear as Microsoft Entra AADSTS codes buried inside lengthy error messages, sign-in logs, and application output. This free browser-based tool helps you quickly identify those codes, understand what they mean, and review practical guidance for resolving common authentication and authorization issues. Paste a single code, multiple codes, or a complete error message to begin.
AADSTS Error Code or Full Error Message
Paste a single AADSTS code, multiple codes, or a complete error message from a Microsoft 365 sign-in log, application response, PowerShell session, or stack trace. You can also enter a term such as consent, redirect, or MFA to search the error descriptions. Matching results appear as you type.
Paste one code, several codes, or a whole error blob from sign-in logs or a stack trace. You can also type a keyword like "consent" or "redirect" to search descriptions. Results appear as you type.
How this works
Microsoft Entra sign-in failures come back as AADSTS codes buried in error messages. This tool matches them against Microsoft's published error code reference (350 codes embedded in this page) and adds practical fix notes for the codes admins hit most often.
Everything runs in your browser from data embedded in this page. Nothing you paste is sent anywhere, so error messages containing usernames or app IDs are safe to drop in.
Descriptions from Microsoft's Entra authentication error code reference. Not affiliated with or endorsed by Microsoft.
How the AADSTS Error Lookup Works
Microsoft 365 relies on Microsoft Entra ID for identity and access management. When an authentication or authorization request fails, Microsoft Entra frequently returns an AADSTS error code within a much longer response.
This tool identifies those codes and matches them against Microsoft’s published authentication and authorization error reference. It provides a faster way to understand Microsoft 365 and Entra sign-in failures without manually searching through a lengthy documentation page.
For commonly encountered errors, the lookup also includes practical troubleshooting notes to help Microsoft 365 administrators and application owners determine what to review next. Depending on the error, this may include an application registration, redirect URI, consent configuration, Conditional Access policy, user account, tenant selection, certificate, or authentication request.
Where You May Encounter AADSTS Errors
AADSTS errors can appear in several areas of a Microsoft 365 environment, including:
- Microsoft 365 application and admin portal sign-ins
- Microsoft Entra sign-in logs
- Microsoft Graph applications and scripts
- Exchange Online and Microsoft Graph PowerShell connections
- Enterprise application authentication
- OAuth and OpenID Connect responses
- App registrations and consent requests
- Applications using Microsoft identities for sign-in
Although these errors frequently appear while administering Microsoft 365, the codes themselves come from the Microsoft Entra authentication and authorization platform.
Search More Than One Error at a Time
You can paste a single code, several codes, or an entire error response into the lookup. This is particularly useful when working with Microsoft Entra sign-in logs, Microsoft 365 administration scripts, application logs, PowerShell output, or stack traces where the AADSTS code may be surrounded by additional diagnostic information.
The lookup also supports descriptive searches. If you do not know the exact error code, enter a keyword related to the problem, such as:
consentredirectcertificatetenantMFAConditional Accessuser disabledinvalid client
Matching error descriptions appear as you type.
Privacy and Local Processing
The lookup runs entirely in your browser using error reference data embedded in the page. Information entered into the tool is not submitted to SeanShares or stored by the lookup.
This makes it possible to paste a complete Microsoft 365 or Entra error message without sending its contents to another service. However, it is still a good practice to review diagnostic data before sharing it with anyone. Error responses may contain usernames, application IDs, tenant details, correlation IDs, trace IDs, and other information associated with your environment.
About the Error Information
Error descriptions are based on Microsoft’s published Microsoft Entra authentication and authorization error code reference. Microsoft may update its error codes, descriptions, and recommended resolutions as the identity platform changes.
This tool is intended to provide Microsoft 365 administrators, developers, and application owners with a convenient starting point for troubleshooting. Complex authentication problems may still require a review of the associated Microsoft Entra sign-in event, Conditional Access results, application configuration, or diagnostic logs.
SeanShares is not affiliated with or endorsed by Microsoft.