Microsoft 365 Global Administrator locked out – Error 399287

Question

Microsoft 365 Global Administrator locked out – Error 399287

Π. Ε. ΚΕΣΙΣΤΟΡΝΟΥ ΟΕ 0

Hello,

I am the only Global Administrator of my Microsoft 365 Business tenant.

I am completely locked out of my administrator account because Microsoft blocks my SMS verification.

I receive error code 399287 (BadReputation) before an SMS is even sent.

Here are my diagnostic details:

Error Code: 399287
Request ID: [Moderator note: Personally Identifiable Information removed]
Correlation ID: [Moderator note: Personally Identifiable Information removed]
Timestamp: 2026-11-07T16:20:42Z

I am the only administrator, so I cannot access the Microsoft 365 Admin Center to create a support ticket.

I specifically request a review and removal of the Phone Reputation / BadReputation block affecting my phone number.

This issue is preventing me from accessing my business subscription and installing Microsoft Office.

Thank you.

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1 answer

Your answer

Answer 1

Hi Π. Ε. ΚΕΣΙΣΤΟΡΝΟΥ ΟΕ,

Welcome to the Microsoft Q&A forum.

Error code 399287 usually appears when the system detects unusual activity on a device that may pose a risk to the tenant. As a result, the system may flag your device as having a bad reputation.

To have the device reviewed and confirmed as safe, you will need to contact the Microsoft Data Protection Team.

Please look up the appropriate Microsoft support hotline for your region and contact Microsoft frontline support. Then, ask the support representative to create a support ticket for you through the following page:

Customer service phone numbers - Microsoft Support

Tips for navigating the IVR system (automated phone support)

To help you navigate the IVR system more effectively, please refer to the guidance below:

When calling the support number, you may hear an introduction that lasts about 30 seconds, for example, “You can visit the link...”. You can skip this and wait until the system presents the available options.

Then:

Press “1” to select the option for business email users.
Press “1” again to select technical support.

In some regions, the initial interaction may be fully automated. Below is a sample dialogue that you can prepare in advance:

What kind of problem are you experiencing? Answer: Authenticator.
What products do you use? Answer: Office 365 for business.
Is this for an education or company account? Answer: For a company account.
Are you an administrator? Answer: Yes.
Are there any other administrators in your organization? Answer: No. I am the only administrator in my tenant.
Do you need a service request? Answer: Yes. I need to create a support ticket. Please transfer my request directly to the Data Protection Team.

During the call, you may be asked to provide subscription-related information, such as:

Company name
Billing information
Phone number
Alternate email address

This information will help the Data Protection Team verify your identity and securely assist you with restoring access.

If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

If the answer is helpful, please click "Yes" and kindly upvote it.

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