error code 500121

Question

I am trying to use the authenticator app to log into a customers portal and getting error code 500121

Answer 1

Hello @Robert Saunders,

Thank you for your message.

The error code 500121 is usually related to multi‑factor authentication (MFA). To help clarify the situation, could you please check this further with your customer?

If possible, please ask whether an administrator on customer's side can revoke and reset the MFA registration for your customer’s account. This will allow your customer to reconfigure the authenticator app and may resolve the issue.

You can share this official Microsoft article with them for guidance: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…   

If there are no available administrators who can perform this action, then your customer's side may need to contact Microsoft Support by phone so the case can be routed to the Data Protection team. This team has the appropriate tools and permissions to verify the account and assist with access issues.

You can find the support phone numbers here: Customer service phone numbers - Microsoft Support

Please let me know once you’ve confirmed with your customer, or if you need any further assistance, I’ll be happy to help.

Kind regards,

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Answer 2

the answer did not solve my problem