Error Code Portal
MicrosoftMicrosoft Entra IDError code

AADSTS501621

ClaimsTransformationTimeoutRegularExpressionTimeout

Alternative forms: 501621

What does this code mean?

Code AADSTS501621 · An issue reported by Microsoft Entra ID.

Official explanation · Original text

ClaimsTransformationTimeoutRegularExpressionTimeout - Regular expression replacement for claims transformation has timed out. This indicates a too complex regular expression may have been configured for this application. A retry of the request may succeed. Otherwise, please contact your admin to fix the configuration.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

Microsoft Entra authentication and authorization error codes ↗

Creator: Microsoft Corporation and contributors
License: Creative Commons Attribution 4.0 International
Checked on: 2026-11-12

Modifications: Extracted official AADSTS table; Markdown stripped; short English error name selected; original Korean product context added. Official general diagnostic guide is distinguished from code-specific troubleshooting. Documentation license explicitly granted by README Legal Notices; repository LICENSE currently contains MIT terms, also retained as evidence.

Source details · Original licenses and notices