Access external shared report/workspace as guest user - error 401

Hi naanii 

An error status of 401 indicates that the request is missing valid authentication credentials for the target resource.

In the Power BI service, users outside your organization can successfully view shared data if you don't set up row-level security.

However, if you set RLS on the semantic model, you must add the users accessing the user to the role, otherwise they won't be able to see anything. Please check your RLS settings and try again.

You can check out the following link, which may help you:
Azure Active Directory B2B Access - Microsoft Fabric Community

You can check if only this one out-of-domain guest account can't view any shared resources.

In the Microsoft Entra ID, you can set an external user as a User Type Member. In Power BI, support for UserType Members is currently in preview. Please note the following:

External members can't currently use their Power BI licenses in their home tenant to access content and perform activities in the provider tenant. Instead, the appropriate licenses must be explicitly granted in the provider tenant. External members are similar to internal users on a provider tenant.

Microsoft Purview Information Protection isn't supported by external members. Admins in the provider tenant are not advised to enable information protection for external members.

In some cases, external members may see an error when they first try to sign in to the provider tenant. To unblock these external members, give them access to Power BI items, such as workspaces, semantic models, or reports, and then have them sign back in.

This link may help you:

Distribute Power BI content to external guest users using Microsoft Entra B2B - Power BI | Microsoft Learn

Best Regards,

Zhengdong Xu

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