📖 Original Reference: Originally published with interactive diagrams and enterprise identity baselines at alexmaina.dev/entra-id-redirect-uri-aadsts50011 .

If you are developing applications using MSAL (Microsoft Authentication Library) and Microsoft Entra ID (formerly Azure AD), you have likely run into this frustrating blocker:

AADSTS50011: The reply URL specified in the request does not match the reply URLs configured for the application '{client-id}'.

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This error appears during the OAuth 2.0 / OpenID Connect authorization handshake. Microsoft's token endpoint performs a strict character-by-character validation , meaning even a single trailing slash or port mismatch will immediately halt authentication.

Here is how to diagnose the root cause and fix it in under 3 minutes.

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