I’m trying to verify my identity using my phone number but I get error 399287

Question

I’m trying to verify my identity using my phone number but I get error 399287

Samir Hendawy 0

My organization created a new account for me, I used same phone number as my personal account to verify this new account. However, I get this error 399287. From help it’s flagging my number as bad repetition but I didn’t do anything harmful using my number or abuse anything. So I need help to remove this flag and check the issue

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Answer 1

Heimerdinger 1,210 Independent Advisor

Hi @Samir Hendawy,

Thank you for posting your question in the Microsoft Q&A forum.

I’m very sorry to hear about your situation.

If you are an end user I would recommend you contact your account's Admin to reset your MFA settings through the Microsoft Entra Admin Center.

Please note I'm just another user here on this public forum, not your organization's admin, so I'm not able to reset or unlock anything on your account myself.

Ask your administrator to follow these steps:       

Revoke MFA sessions and require re-register in the Microsoft Entra admin center 

Sign in to Microsoft Entra admin center with the admin account
Go to Users
Select the affected user account
Open Authentication methods
Revoke sessions
Select Require re‑register MFA
Save the changes

Revoke MFA sessions and require re-register in the Microsoft Entra admin center 

User's image

You could provide your admin this article for a better view: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…    

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

Thank you again for your time and understanding. I really appreciate your patience, and I’m here to help. Looking forward to your response.          

Samir Hendawy 0 Reputation points

2026-10-12T12:35:15.94+00:00

Hi @Heimerdinger

this is a new user and first time login so why did the issue happen in the first place?
Heimerdinger 1,210 Reputation points Independent Advisor

2026-10-13T13:23:34.7066667+00:00

Hi @Samir Hendawy,

Unfortunately, the reason behind a "bad reputation" or similar flag is not something that forum users can verify. As I'm also just a user on this public forum, I don't have access to Microsoft's backend systems, authentication logs, risk assessments, or internal data that would show why error 399287 was triggered.

I would recommend raising a support ticket through your Microsoft 365 administrator so that Microsoft Support can investigate the issue directly. The support team has access to the internal tools and diagnostic information needed to determine whether the phone number was incorrectly flagged and whether any remediation is available.

The Global Admin should create a service request with Microsoft support to get advanced technical assistance and diagnostics. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin.   

Your administrator can contact Microsoft Support from the Microsoft 365 Admin Center and provide the affected account details, the phone number involved, and the exact error code (399287) to assist with the investigation.

Thank you for your understanding. I hope this information helps. Please let us know if you have any additional questions.