Error Code: 399287 while sign into Microsoft 365 portal

Question

Error Code: 399287 while sign into Microsoft 365 portal

Giang Nguyễn Trường 20

Dear Microsoft Support Team,

I'm trying to sign into the Microsoft 365 portal. I can sign in to my Microsoft account, but I'm prompted to verify my identity via SMS. However, I receive the following error message:

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

Error Code: 399287

Request Id: [Moderator note: Personally Identifiable Information removed]

Correlation Id: [Moderator note: Personally Identifiable Information removed]

Timestamp: 2026-07-06T01:22:17Z

I have already tried alternative login methods and password reset options but have been unable to complete the identity verification process. I would appreciate your assistance in resolving this issue as soon as possible. It would be great if you could unblock the MFA to the account.

I am using another email to post this question since i am not able to access my main account. You can contact me on this email.

Thank you for your kind support

Best Regards,

0 comments

Answer accepted by question author

Jade Ng 13,570 Microsoft External Staff Moderator

Dear @Giang Nguyễn Trường,

Regarding the issue where you are receiving error code 399287 and are unable to receive or use the SMS verification code to sign in, I’d like to ask a question to better understand your situation and assist you more effectively.

Could you please clarify whether you are an end user or an admin?     

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. Ask your administrator to follow these steps:       

Sign in to the entra.microsoft.com as at least one Authentication Administrator.
Select User > All user. Select the user (your account) to act on and select Authentication methods then select Require re-register of multi-factor authentication.

Require re-register MFA: This disables all previous authentication methods. You'll then be prompted to configure a new MFA authentication method the next time you try to sign in, so you can set up from the start and add a new authenticator app.

Untitled

For step-by-step details, see the official Microsoft documentation: Manage authentication methods for Microsoft Entra multi-factor authentication - Microsoft Entra ID | Microsoft Learn

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

Note: Once re-registration is triggered, all your existing MFA methods such as phone numbers, Authenticator app, or other verification options will be removed. You will need to set up new MFA methods during your next login. Please ensure you have access to a valid phone number or the Microsoft Authenticator app before attempting to sign in again.

Please feel free to contact me if you are an admin. I appreciate your patience, and I am here to help. Looking forward to your response!

Giang Nguyễn Trường 20 Reputation points

2026-07-06T02:27:55.56+00:00

I'm an admin. I can't login into microsoft authenticator app because the same error code 399287
Jade Ng 13,570 Reputation points Microsoft External Staff Moderator

2026-07-06T02:50:03.5933333+00:00
Dear @Giang Nguyễn Trường,

Thank you for your response!

Could you please tell me is there any other global administrator in your organization? If so, I recommend you contact him/her to raise a request for resetting your authentication method in the Entra admin center. Other admins can revoke MFA sessions and require re-registration in Microsoft Entra admin center.

But if you are the only admin and cannot access your account due to an authentication issue, it is suggested to contact the Data Protection team as we are from the community team and are not authorized to reset any user/admin accounts. The data protection team is the only support team to verify and reset the account.

For a full list of regional numbers, you can also visit this official page: Customer service phone numbers - Microsoft Support. The support team will assist you as soon as possible.

If you can reach Microsoft by phone, use the official Global Customer Service phone numbers list. Choose your region > your country > if your country lines fail or lack English support, select a nearby country or the United States number, Microsoft explicitly allows this.

If you have difficulty reaching an agent by phone, there is a reliable workaround. This involves creating a new, temporary Microsoft 365 account to contact the support team online.

1.Visit the Microsoft 365 Enterprise Plans page: Go to Compare Office 365 Enterprise Pricing and Plans | Microsoft 365.

2.Choose a plan and start a free trial: Select any of the available plans and click "Try for free" to begin the trial setup process.

3.Follow the guided setup: Complete the steps to create a new Microsoft account and a new tenant. This will be a separate and independent Microsoft 365 environment.

4.Access the Microsoft 365 Admin Center: Once the new tenant is created, navigate to https://admin.microsoft.com/AdminPortal/Home#/homepage

5.Go to Support: In the left-hand navigation menu, click on "Support" and then "Help & support."

6.Raise a support ticket: Describe your issue in detail. Crucially, you must clearly state that you are locked out of a different, pre-existing Microsoft 365 tenant where you are the administrator. Provide the following information about your locked account:

Your administrator account email address for the tenant.

The domain name of your tenant

Any error messages you are receiving.

Details about the issues you are experiencing

Confirmation that you are the administrator of the tenant.

7.Submit your ticket:

Follow the prompts to submit your support request. You will likely receive a ticket number for tracking.

Important notes:

This new trial tenant will not give you access to any of the data or settings in your original locked tenant. It is solely a temporary means to contact Microsoft support.

Be prepared for Microsoft support to ask for verification of your identity and administrative rights for the locked tenant.

The resolution time might be longer as you are contacting support from a different tenant.

Remember to cancel the trial subscription for the new tenant once your issue with the original account is resolved to avoid any unintended charges. You can typically do this within the Microsoft 365 Admin Center under "Billing" > "Your products."

I hope these steps will help resolve your issue. If you need further assistance, I am always here to help.

Thank you for your patience and understanding. I appreciate your continued trust. Hope you having a nice day and really much warm regards to you as well!

1 additional answer

Your answer

Giang Nguyễn Trường 20 Reputation points

2026-07-06T02:27:55.56+00:00

I'm an admin. I can't login into microsoft authenticator app because the same error code 399287

Answer 1

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