Unable to Access M365 Account – Error 399287

Question

Unable to Access M365 Account – Error 399287

Dominic Hodpel 35

I am encountering an issue logging into my Microsoft 365 account due to a problem with MFA. My phone was changed several months ago, so I no longer have access to the original MFA method. When I try to verify my identity via SMS, I receive the following error:

“Sorry, we’re having trouble verifying your account. Please try again.”

Error Details:

Error Code: 399287

Request Id: 28ff5656-b048-49b8-ac2c-eb98a3b74c00

Correlation Id: cadb36f0-096f-42cf-b8be-b0ad76befe64

Timestamp: 2025-08-23T00:26:35Z

I would appreciate a prompt resolution to this problem. Please let me know what information is necessary from my side to proceed.

Thank you for your support.

Raja Pothuraju 46,030 Reputation points Microsoft External Staff Moderator

2025-08-23T09:50:16.2866667+00:00

Hello Dominic Hodpel,

Kindly share the affected email address, phone number and country name via private message.

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Raja Pothuraju 46,030 Reputation points Microsoft External Staff Moderator

2025-08-23T09:50:16.2866667+00:00

Hello Dominic Hodpel,

Kindly share the affected email address, phone number and country name via private message.

Answer 1

Raja Pothuraju 46,030 Microsoft External Staff Moderator

Hello Dominic Hodpel,

Thank you for sharing your details.

I’ve reached out to the engineering team regarding the MFA issue on your account. They have now unblocked it from the backend and cleared the bad reputation associated with it. You should be able to log in to the Azure Portal without any issues.

Please try signing in and verify if you can complete SMS authentication successfully. Let me know if you encounter any problems.

As a best practice, I recommend registering the Microsoft Authenticator method for your account instead of relying on SMS. SMS and voice call authentication methods are more vulnerable to IRSF attacks (telephony fraud) and are generally less secure.

For better practice, I recommend registering with Microsoft Authenticator method to your account instead of SMS method as these SMS/Voice telecom auth methods are susceptible to IRSF attacks telephony fraud.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

Arturas Babickas 20 Reputation points

2026-02-19T12:22:37.7233333+00:00

Hello @Raja Pothuraju

could you please also help? we have identical issue with new tenant. If need, i can provide more information

Technical Details for Engineering:

Error Code: 399287

Request ID: 098868f4-ec94-49e0-bb44-13486b98ed00

Correlation ID: 37538264-b522-4a40-aefa-8a2fbae8a739

Timestamp: 2026-02-17T07:09:49Z
Raja Pothuraju 46,030 Reputation points Microsoft External Staff Moderator

2026-02-19T13:04:55.5466667+00:00

@Arturas Babickas, I recommend creating a new thread on the same Q&A forum with as many details about your issue as possible. This will ensure better visibility within the community.

Please create a new Q&A post at https://learn.microsoft.com/en-us/answers/questions/ask/ and select the Microsoft Security | Microsoft Entra | Microsoft Entra ID tag when submitting your question.
Arturas Babickas 20 Reputation points

2026-02-23T07:16:43.0233333+00:00

@Raja Pothuraju https://learn.microsoft.com/en-us/answers/questions/5784678/new-tenant-mfa-error-399287-sms-error

thank you

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