VEMULA | Unable to Verify Identity for Azure Login – Error 399287

Question

Hi VEMULA

or anyone who can assist me please.

I have tried reaching out to Microsoft directly but to no avail.

I have this same issue, my number is "flag" for unknow reason and now i cannot log in to my admin Portal.

I have this issue for 2 weeks and really need assistance.

Please unblock my number so i can get the SMS to log back into my tenant.

AJ

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Moved from: Microsoft Security | Microsoft Authenticator

Answer 1

Hello @Andries Jacobs

Based on the issue described, this appears to require direct assistance from Microsoft Support, as the problem is related to the identity verification/ MFA sign-in process and cannot be fully resolved through the Q&A forum.

At this point, the recommended next step would be to contact Microsoft Support using one of the following options:

1. If there is another admin in the tenant

That admin may be able to help update or reset the authentication methods tied to your account so you can sign back in and re-register Authenticator on your new phone. Please refer to this article https://learn.microsoft.com/en-us/entra/identity/authentication/howto-mfa-userdevicesettings#manage-user-authentication-options

 2. If you are the only admin

In that case, this usually requires direct account recovery or Microsoft business support assistance, since forum support cannot bypass or manually remove MFA from a locked business tenant. Please proceed with one of the support options below to initiate the Data Protection/ Tenant Recovery process:

Customer service phone numbers

Here are some tips and an example of a prompt to help you navigate the IVR more effectively:   

(When you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help)        

During the call, you will be asked to provide information that verifies your identity and proves ownership of the tenant, such as your organization name, billing information, contact email, phone number, or other subscription‑related details.

If you are unable to reach support via the phone numbers, there is a workaround you might consider: You can register for a new Microsoft 365 tenant by signing up for a trial subscription here: https://www.microsoft.com/en-us/microsoft-365/business/microsoft-365-plans-and-pricing

Once the new tenant is created, you can access the admin center and submit a support ticket from there, requesting to speak with the Data Protection Team on behalf of your original tenant. Important notes:

This new trial tenant will not give you access to any of the data or settings in your original locked tenant. It is solely a temporary means to contact Microsoft support.

The resolution time might be longer as you are contacting support from a different tenant.

Remember to cancel the trial subscription for the new tenant once your issue with the original account is resolved to avoid any unintended charges.

If possible, it would also be helpful to have the following details ready during the recovery process:

• Tenant domain name (yourcompany.onmicrosoft.com or custom domain)

• Company/ organization name

• Billing or contact email address

• Recent invoice/ payment reference (if available)

• Subscription name or product type (if known)

I hope this helps point you in the right direction.

Answer 2

Error 399287 and a “bad reputation” flag on the phone number cannot be cleared from the admin side; this must be handled by Microsoft support/Data Protection.

Based on similar resolved cases, the path forward is:

1. If there is another global admin in the tenant
   • That admin should sign in to the Azure portal → Microsoft Entra ID → Users → select the affected account → Authentication methods → select Require re-register multifactor authentication.
   • After this, sign-in will prompt for MFA registration again, where a different phone number or method (such as Microsoft Authenticator) can be configured.
2. If there is no other global admin (you are the only admin)
   • This scenario must be handled by the Microsoft Data Protection / Tenant Recovery team. Forum moderators and other users cannot unblock the number or reset MFA.
   • Contact Microsoft support by phone and clearly state:
     • The issue is MFA / authenticator / SMS verification not working.
     • It is for a company/organization (work account), and this is the admin account.
     • There are no other admins.
   • The frontline agent must open a service request and route it to the Data Protection team, who can verify identity and reset MFA/unblock the number on the backend. This is how similar “bad reputation” / 399287 cases were resolved.
3. If direct support contact is difficult
   • As described in a similar case, it is possible to create a temporary Microsoft 365 trial tenant, go to the Microsoft 365 admin center for that trial, and use Support → Help & support to open a ticket.
   • In that ticket, clearly state that the problem is with a different, existing tenant where the admin is locked out due to SMS/MFA issues and error 399287, and provide the locked tenant’s admin UPN and domain so support can route the case to Data Protection.

Only Microsoft support/Data Protection can remove the “bad reputation” flag and/or reset MFA when the only registered method is blocked.

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References:

• You don't receive a text or voice call that contains the verification code for Microsoft Entra multifactor authentication
• I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A
• Global Admin Locked out - Microsoft Q&A
• Azure has blocked myphone number for SMS verification due to a “bad reputation” flag - Microsoft Q&A
• Microsoft Q&A Unable to Verify Identity for Azure Login – Error 399287