I created and tested tabular model in VS without any roles. I connected to PBI desktop and created simple report. I created gateway and successfully connected using service account (admin in SSAS) to SSAS.
Report was successfully uploaded to service and but then I got error.
First error was "User does not have access to the db or db does not exists" so i created role in ssms and added user with read permissions.
After deploy I got error: It seems user has permissions, but something else went wrong.
I checked some tutorials how to use PBI with SSAS but with no luck.