problem login on outlook with my email

Hi @info,

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

From the screenshot, I can see that Microsoft is asking you to verify your identity, but the verification is failing with error code 399287 while trying to use the phone number registered for multifactor authentication (MFA).

To better understand your situation and provide the most appropriate guidance, could you please clarify the following:

1. Are you an end user or the Microsoft 365 administrator for this account?
2. Are you able to access the account on your old computer or any other device?
3. Did you recently change your phone number, replace your phone, or lose access to the Microsoft Authenticator app?

If you are an end user and you no longer have access to your MFA verification method, I would recommend contacting your organization's Microsoft 365 administrator and asking them to reset your MFA settings through the Microsoft Entra Admin Center.

Your administrator can:

1. Sign in to the Microsoft Entra admin center using an administrator account.
2. Go to Users.
3. Select the affected user account.
4. Open Authentication methods.
5. Select Revoke sessions.
6. Enable Require re-register MFA.
7. Save the changes.

You may also share the following Microsoft article with your administrator for detailed instructions:

• Manage authentication methods for Microsoft Entra multifactor authentication

If you're unsure who the Microsoft 365 administrator is within your organization, you can refer to:

• How do I find my Microsoft 365 admin?

Additionally, please ask your administrator to review the sign-in logs using the information shown in your screenshot:

• Error Code: 399287
• Correlation ID:
• Timestamp:

These details may help them identify the exact cause of the authentication failure.

Please note that I'm also a user, so I don't have access to user accounts and cannot assist with actions such as resetting MFA methods, changing sign-in settings, or recovering access to your account.

Thank you again for your time and cooperation. I look forward to your response.