Power BI Report Server interaction with SSAS Multidimensional Cube with row-level security

Hi,

We have SSAS multidimensional cube configured with row-level security. We have a Power BI Report Server configured with the live data source connecting to the cube. We are using Windows authentication with "Log in using these credentials, but then try to impersonate the user viewing the report " checked. When we test the connection we are getting the following error:

"XML for Analysis parser: The 'Domain\Username' value of the 'EffectiveUserName' XML for Analysis property is not valid."

The goal is logged in user credentials pass to the SSAS Cube for it to respond effectively with row-level security. Does anyone know where any configuration changes need to be made. To note the 'Domain\Username' is an administrator of the analysis services database. 

Thanks,

Sunil