Unable to login admin.microsoft.com, problems with sms

Question

Since unknown period, I can't login to admin.microsoft.com for two of my customers. A time ago I had setup verification through sms, but unfortunately that doesn't work anymore. Restoring password or login doesn't work, neither with alternative mailaddress, last step is verification with sms again.

In Dutch I get the error: "Uw account is niet geverifieerd. Probeer het opnieuw."

In English this means: "Your account is not validated. Please try again."

What can I do to restore my access? I'm the only admin in these tenants.

Error Code: 399287

Answer 1

Hi @Alex Van brunschot,

I hope you are doing well.

Thank you for taking the time to share your experience. I hope this response reaches you in time and helps bring some clarity.

I’ve gone through your description, and I’m sorry to hear about the difficulty you are experiencing when trying to access your work account due to issues with SMS. Please know that you’re not alone, as many users encounter similar challenges.

 

Unfortunately, forum moderators do not have the ability to access, modify, or recover user accounts. Due to security and privacy requirements, issues such as sign in failures, password recovery, and multi factor authentication can only be addressed by Microsoft’s dedicated support teams, who have the appropriate tools and authorization to manage account level settings securely.

These scenarios require identity validation and tools that are strictly handled by dedicated support teams for security reasons. Since you are the only administrator of your tenant and you’re currently unable to sign in, the next essential step is to involve the Microsoft Data Protection team, as they are the only team authorized to help recover an admin account in these circumstances. You can start by calling your regional Microsoft support hotline here: Customer service phone numbers - Microsoft Support   

During the phone call, you will need to provide the information associated with your subscription, such as your company name, billing details, phone number, and an alternate email address, etc. This information allows the Data Protection team to verify your identity and securely assist you in regaining access to your administrator account.      

In some regions, the initial interaction may be automated, so here’s a general idea of how the conversation might go to help you prepare:     

Here are some tips and an example of a prompt to help you reach out the Microsoft Data Protection team support 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.)        

In some countries, it is an automated conversation like: 

IVR: What kind of problem are you concerned about?       

You: Authenticator.       

IVR: What kind of product do you use?       

You: Office 365 for business.       

IVR confirmation: education or company account?       

You: For companies       

IVR: Are you an administrator?       

You: Yes.       

IVR: Do you have another administrator in your organization?       

You: No.       

IVR: Do you need a... Service request?

You: Yes. I need to create a ticket. Please send me directly to the Data Protection Team.

I truly hope this helps you regain access to your account quickly. Even though I can't directly intervene, directing you to the correct and specialized support is the most effective help I can provide from my position. 

Thank you for your kindness and contributions to the forum. 

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Answer 2

Error code 399287 and the message that the account is not verified indicate that SMS-based verification for the admin account is blocked or failing, and no other MFA method is available. Because the account is the only admin in each tenant, this must be handled by Microsoft support/Data Protection.

To restore access in this situation:

1. Do not keep retrying SMS
   • Excessive or repetitive verification attempts can cause or extend blocks on the account or phone number and lead to further issues with verification codes.
2. Use the sign-in helper if available
   • For sign-in issues, use the Microsoft sign-in troubleshooter to identify the problem and see available support options: Start.
3. Contact Microsoft support / Data Protection team
   • For tenants where there is only one admin and that admin is locked out due to MFA/SMS issues, the documented resolution is to involve Microsoft’s Data Protection team via Microsoft Support.
   • Customer service can reset MFA or clear the bad reputation/blocked status on the phone number and help regain access. Similar cases with error 399287 and single-admin tenants were resolved this way.
   • If the subscription is through a partner/reseller and the global admin cannot open a service request, the reseller’s support provider can open a service request on behalf of the tenant.
4. If needed, create a temporary trial tenant to open a support ticket
   • If direct access to support is not possible because of the lockout, a separate Microsoft 365 trial tenant can be created solely to contact support:
     • Create a new Microsoft 365 tenant with a trial plan.
     • Go to the Microsoft 365 Admin Center for that trial tenant and open a Support → Help & support request.
     • Clearly state that the issue concerns a different, existing tenant where the account is the only admin and is locked out due to SMS/MFA with error 399287.
     • Provide the admin UPN, tenant domain, and the error details so support can route the case to the Data Protection team.
   • This trial tenant is only a channel to contact support; it does not provide access to data in the locked tenants and should be cancelled after resolution.

Once Microsoft support/Data Protection has verified identity and reset MFA or cleared the SMS block, sign-in to admin.microsoft.com should succeed, and new MFA methods (such as Microsoft Authenticator) can be configured to avoid future SMS issues.

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References:

• Troubleshoot Microsoft verification code issues
• You don't get an email message or text message when you reset your admin password for Office 365, Azure, or Intune
• Common problems with two-step verification for a work or school account
• 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
• 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
• MFA admin account no longer works - Microsoft Q&A
• Having problems getting text codes to confirm my account - Microsoft Q&A

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