Thanks for the reply...
Uninstalled, downloaded the latest, installed and it worked out of the gate under the NT SERVICE\PBIEgwService service but as soon as I change it to a domain account, it errors out with the error message above.
looks as though the user mapping you're referring to is marrying up users cloud identities to user accounts\roles on the SSAS models themselves or subset of data within the model.
I'm looking to change it so the service runs under a domain level account vs a local account.
thoughts..?
UPN Mapping
Starting today, customers using Analysis Services with the Power BI Gateway will be able to set up their own UPN mapping rules. UPN Mapping enables gateway admins to apply custom security rules by mapping users’ cloud identity to specific on-prem roles or identities, via Effective User name and CustomData properties on an AS connection.
This feature will be rolled out in 2 phases: Using Effective User name, which is now available, and using CustomData property, which will be available soon.
To start creating new mapping rules, you need to go to the “Manage Gateways” option from your Power BI dashboard, and then choose the Gateway and Analysis Services server to which you want the rules to be applied.
Click on the Users tab and notice the new “Map user names” option. This will open the UPN mapping rules pane and you can start creating rules, changing their order, and testing the user names that you’d expect to change based on the rules. These rules will be applied to the selected data source only and not the whole Gateway. Please note that you need to be a Gateway Admin to set up or modify these rules.
