Error code 399287 when try receive security code

Question

I recently changed my phone. when i move to new phone, i cleared the old ones and installed authenticator on my new phone. However, when I signed in my work account, the app asked me the code on the authenticator apps on the other phones but i reset the old phone. When i try using texting phone number, The app showed error code 399287. Now i cannot log in my work account and receive security code

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Moved from: Microsoft Security | Microsoft Authenticator

Answer 1

Hello @Hoang Xuan Bach

Welcome to the Microsoft Q&A Community! 

Please note that this forum is a public platform, so we’ve adjusted your question to hide your organization’s domain name. For future posts, kindly avoid sharing any personal or organizational details to help protect your data. 

Thank you for contacting us. I understand you’re unable to sign in due to the MFA prompt failing and seeing error code 399287. This error often occurs when the phone number used for Multi‑Factor Authentication (MFA) is flagged by Microsoft’s PhoneReputation system as having low or suspicious reputation. When this happens, SMS and phone call verification may be blocked, even if the number works normally elsewhere. This behavior matches what is described in Microsoft’s support guidance. 

Before we proceed, I need to confirm two details so I can guide you through the correct recovery steps: 

1. Are you signed in with a personal account (e.g., @hotmail.com, @outlook.com), an education account (e.g., @school.edu), or a work account (e.g., @yourcompany.com)?  
2. If this is a Work or School account, do you have global admin permissions for your organization’s Microsoft 365 tenant? 

If you have a user account without admin permissions, kindly ask the one who is having the Admin permission to help you reset your MFA settings through the Microsoft Entra Admin Center. 

If you’re unsure who the Admin is within your school, you can find guidance on locating them here: How do I find my Microsoft 365 admin? - Microsoft Support 

Please have your administrator follow the steps shown in the following article: Manage authentication methods for Microsoft Entra multi-factor authentication - Microsoft Entra ID … 

• Go to Microsoft Entra admin center > Users > Your Name > Authentication methods 
• Remove the old Authenticator registration 
• Select Require re‑register MFA 
• Save changes  After this, try signing in again and you should be prompted to set up your MFA from scratch. 

 In case you are the only global admin and cannot access the admin center, you’ll need to contact Microsoft’s official support hotline for your region, listed under the Customer service phone numbers page. They can help verify your identity and reset your MFA methods. 

If you cannot successfully speak to a support representative, please consider creating a new tenant by signing up for a trial Microsoft 365 subscription via this link Compare All Microsoft 365 Plans | Microsoft. Once the new tenant is set up, use its admin console to submit a support ticket requesting assistance for your original tenant. Remember to cancel the trial subscription after the issue is resolved to avoid charges.  

I hope these steps help resolve your issue. Please let me know if you have any additional questions or need further clarification.  

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Answer 2

عذرا اننا نواجة مشاكل مايكروسفت