Hi @PerizatShatyrbekova-3025
Thank you for asking this question on the **Microsoft Q&A Platform. **
In this thread, there is a solution:
Error Code: 500121
This typically occurs when authentication failed as part of the multi-factor authentication (MFA) request, it may indicate a configuration or service error. To resolve this issue, can you try resetting (require re-register) MFA for your user.
![]()
Related issue - https://github.com/MicrosoftDocs/azure-docs/issues/23238
Hope this helps,
Carlos Solís Salazar
----------
Accept Answer and Upvote, if any of the above helped, this thread can help others in the community looking for remediation for similar issues.
NOTE: To answer you as quickly as possible, please mention me in your reply.