IT Error Decoder

Entra ID errors

Sign-in and authorization failures from Microsoft Entra ID (formerly Azure AD). AADSTS error codes, Conditional Access blocks, missing consent, and app registration problems.

Every Entra error you'll see comes with an AADSTS code. That code is the most specific information you have — Microsoft documents most of them at learn.microsoft.com, and the number tells you exactly which authentication step failed. The trick is mapping the code to the right place to fix it: app registration, Conditional Access policy, user object, or tenant configuration. The pages here cover the most common AADSTS codes and where to look for each.

20 errors in this category.

All Entra ID errors

Frequently asked questions

What does AADSTS stand for?

Azure Active Directory Secure Token Service. Every code starts with AADSTS followed by a number. The number is the specific failure reason; the message is descriptive but the number is what to search.

Where do I find Sign-in logs?

Microsoft Entra admin center → Users → select user → Sign-in logs (or for tenant-wide: Monitoring → Sign-in logs). They show every authentication attempt with the AADSTS code and the Conditional Access result.

Why does the same sign-in work in incognito?

Cached SSO tokens. Your normal browser may be reusing a stale account selection. Incognito forces a fresh sign-in, which often surfaces the real cause (or works because there's no stale state).

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