@kasiaw29 : When you say "I set up PowerBI in my company (with PowerBI Gateway)" you are referring to gateway setup right? . Power BI service is part of office365 and its managed by tenanent and office365 admins. If you want to setup and use the gateway server with a generic service user, you can do so when you upgrade the gateway or re-install the gateway. Alternatively , you can add the service user to the admin list of the gateway which is up and running. You can see the list of users who have admin access by going to "manage gateway".
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