Graph api, keep getting "Access to the resource is forbidden"

Hi Anonymous ,

Thanks for your question in Microsoft Fabric Community.

Power BI does not support authenticating to Microsoft Graph API using only user credentials (username and password), particularly in the context of scheduled refresh in the Power BI Service.

This is because Microsoft Graph requires authentication using OAuth 2.0, and all flows depend on a registered Azure AD application. Whether you're using delegated permissions (on behalf of a user) or application permissions (for service-level access), the presence of an App ID is required to issue an access token.

In Power BI Desktop, you might see prompts for user credentials when connecting via OData feed (e.g. https://graph.microsoft.com/v1.0/users). However, this delegated approach does not work when you publish the report to Power BI Service, as the service cannot impersonate a signed-in user or manage delegated tokens. As a result, you encounter the "Access to the resource is forbidden" error.

The supported and secure approach is to register an application in Azure AD, assign the necessary Microsoft Graph API permissions (such as User.Read.All), and authenticate using an App ID and either a client secret or certificate. This method is compatible with Power BI’s scheduled refresh model.

To avoid hardcoding secrets, you can store credentials securely in Azure Key Vault and reference them in Power BI Dataflows, which offers a cleaner and more secure setup. As tharunkumarRTK  suggested, using a custom connector is also a valid path if you need more control over the API calls or token handling.

Here are some similar and useful resources:
Solved: Service Principal authentication (for Graph API) w... - Microsoft Fabric Community

Authentication and authorization basics - Microsoft Graph | Microsoft Learn

Choose a Microsoft Graph authentication provider - Microsoft Graph | Microsoft Learn

Hope this helps. Please reach out for further assistance.
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