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I have an Error Code: 399287

José Gonçalves 20 Reputation points
2025-11-17T20:04:22.0766667+00:00

I cannot login because i only have an global admin and the 2FA is a mobile phone.

But I cannot receive the SMS because error 399287 appears.

I need to unlock the SMS number, please.

Microsoft Security | Microsoft Entra | Microsoft Entra ID

Answer accepted by question author

Shubham Sharma 17,675 Reputation points Microsoft External Staff Moderator
2025-11-17T20:59:07.0933333+00:00

José Gonçalves

Thank you for sharing your details via private message.

I’ve reached out to the engineering team regarding the MFA issue on your account. They have now unblocked it from the backend and cleared the bad reputation associated with it. You should be able to log in to the Azure Portal without any issues.

Please try signing in and verify if you can complete SMS authentication successfully. Let me know if you encounter any problems.

As a best practice, I recommend registering the Microsoft Authenticator method for your account instead of relying on SMS. SMS and voice call authentication methods are more vulnerable to IRSF attacks (telephony fraud) and are generally less secure.

For better practice, I recommend registering with Microsoft Authenticator method to your account instead of SMS method as these SMS/Voice telecom auth methods are susceptible to IRSF attacks telephony fraud.

If the query has been resolved, please take a moment to accept the answer and upvote it 👍 to make it helpful to the community.

Thank you for helping to improve Microsoft Q&A!

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