MTO Portal MFA Prompt Not Loading

Yes, this behavior is currently affecting several organizations that use the Microsoft 365 Defender Multi-Tenant Organization (MTO) portal, and it started appearing after the August–September 2025 portal update. The issue occurs because of a recent backend change in how the MTO portal handles cross-tenant authentication prompts for tenants that enforce MFA or Conditional Access policies with modern interactive tokens.

In previous versions, the MTO portal handled the “MFA Login Required” prompt natively in a pop-up window, allowing admins to authenticate into each tenant directly. After the update, the authentication pop-up now fails to persist its session token within the MTO browser context. As a result, the MFA window flashes and closes immediately, showing the “Loading completed with errors” message and the “Couldn’t receive full data from X of Y tenants” warning.

You can confirm this is the same issue by opening your browser’s developer console while reproducing the problem . you’ll see AADSTS50058 or interaction_required errors, which indicate the token could not be refreshed within the embedded frame.

There are a few temporary workarounds:

Re-authenticate each tenant in a separate Defender tab, then refresh the MTO portal. If the session token is cached in your browser, MTO can retrieve data for those tenants until the session expires.

Disable third-party cookie blocking or strict privacy settings in Edge/Chrome, which sometimes prevent the embedded login window from maintaining state.

Use an Azure Lighthouse delegation instead of MTO for cross-tenant hunting or reporting. Lighthouse integrations continue to support seamless MFA handling because they use service principal authentication rather than interactive login.

Open a support ticket under the MTO service category, referencing the MFA prompt regression tracked internally as bug. Microsoft has confirmed it and is preparing a fix to re-enable persistent cross-tenant sessions in the next Defender portal refresh cycle.

For now, the problem is not specific to your configuration. It is a product-side issue introduced with recent authentication flow updates in the MTO portal, and the fix is in progress. Please hit like if you like the solution.