Lost access to sole Global Admin account – MFA blocked – Need support

Question

Lost access to sole Global Admin account – MFA blocked – Need support

Chien Le 20

Hello Microsoft Support,

I am the sole Global Administrator of our tenant rf2m.onmicrosoft.com. The account ******@rf2m.onmicrosoft.com is locked out due to MFA (SMS) being blocked, likely due to phone reputation issues.
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I cannot log in, and there are no backup admin accounts. I have the following error when trying to sign in:

Error Code: 399287
Request Id: b2aba6a6-a978-417b-91d4-112f3e7d0900
Timestamp: 2025-08-13T08:25:48Z

Please escalate this to the Data Protection Team or provide instructions for tenant admin recovery. I am ready to verify ownership via billing or domain DNS.

Thank you for your support.

Raja Pothuraju 29,730 Reputation points Microsoft External Staff Moderator

2025-08-13T09:57:36.6033333+00:00

Hello Chien Le,

This issue doesn't require to involve Data Protection team. Kindly share the affected email address, phone number and country name via private message.

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Raja Pothuraju 29,730 Reputation points Microsoft External Staff Moderator

2025-08-13T09:57:36.6033333+00:00

Hello Chien Le,

This issue doesn't require to involve Data Protection team. Kindly share the affected email address, phone number and country name via private message.

Answer 1

Hello Chien Le,

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.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

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Lost access to sole Global Admin account – MFA blocked – Need support

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