Unable to Verify Identity for Microsoft 365 Login – Error 399287 because did not provide alternative method of confirmation

Question

I recently change to a new phone. I did not cloning because I do not want to inherit some of the old unused apps.

I forgot about the Microsoft Authenticator app until I log onto a new device. Then I just realized it was still on the old phone which is no longer at my disposal.

To work around it, after a few youtube videos, I decided to turn OFF MFA for the Authenticator App temporarilly so that it configure the app on the new phone then turn it back ON

So I update the policy to turn off everything except SMS and Email OTP.

Clearly, I must have missed some steps—MFA is still enabled, and SMS isn't working even though it's turned on

I managed to contact Microsoft Support and have raised a ticket, but I'm still waiting for their response.
I think Raja Pothuraju solution to unblocked it from the backend and cleared the bad reputation associated with it is the answer.

Thank tou in advance

Answer 1

Hello Mohd Azali Md Adnan

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.

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