2FA Office 365 - Blank page

Hi Mirko,

Thank you for providing such a detailed breakdown of the issue.

Modern Microsoft authentication (including Office activation and MFA prompts) relies on components such as the Microsoft Edge WebView2 runtime and the Web Account Manager (WAM), which are closely tied to user profiles. These authentication interfaces are rendered through WebView2.

In your scenario, the issue seems to be introduced during the Sysprep process, particularly when capturing the image with CopyProfile=True. This setting copies the administrator’s profile state into the Default User profile, which in Windows 11 can disrupt the proper initialization of user-specific components. As a result, critical elements like the Microsoft AAD Broker Plugin responsible for rendering authentication dialogs may fail to function correctly, leading to the blank MFA page you are experiencing.

Microsoft warns against using CopyProfile to handle modern Windows layouts because encrypted users-specific hashes break when copied to other users.

For reference, please consult:

Customize the default user profile by using CopyProfile | Microsoft Learn

Authentication automatically fails in Microsoft 365 services - Microsoft 365 | Microsoft Learn

Issues with AppX, MSIX, or Microsoft store applications - FSLogix | Microsoft Learn

At this stage, while we have identified some likely contributing factors (such as profile-level configuration and authentication components affected during the imaging process), the exact root cause cannot be fully confirmed yet.

To proceed further, this will require a deeper investigation into the backend and system-level configurations. This includes reviewing how authentication services (such as the Web Account Manager and related components) are provisioned and initialized in the deployed environment, as well as validating whether any settings or states carried over during the imaging process may be impacting the sign-in flow.

This issue needs a more in-depth review, which may involve collecting diagnostic logs and examining the system configuration in detail. Given the nature of the problem, the most effective next step is using your admin credentials to submit a support request through the Microsoft 365 Admin Center .

 Microsoft also provides customer service phone numbers based on your region. You can find the appropriate contact number here: Customer service phone numbers - Microsoft Support 

This route ensures that a Microsoft support engineer can initiate a remote session to investigate backend configurations, run advanced diagnostic tools, and, if necessary, escalate the case to specialized teams with access to internal systems and logs. These backend resources are essential for resolving issues that go beyond what’s visible in the user interface.

As community moderators, we’re here to guide you, but due to privacy and security limitations, we don’t have access to the backend tools required for a full resolution. For this reason, contacting Microsoft Support via the Admin Center is the most secure and efficient way forward.

I hope this helps you resolve the issue quickly. I’m glad to assist and truly hope the information provided has been useful. Please feel free to reach out anytime if you need further assistance.  

If you find my post helpful, kindly consider marking it as the accepted answer. Doing so can assist others in the community who may have similar questions in finding solutions more quickly.  

Thank you for your kindness and contributions to the forum. 

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