Dynamic Row-Level-Security not working in service

Hi All!

I have a report where I set up dynamic row level security.

I have a brand_user assignment table, which contains the following fields:

• id (counter)
• user name - name
• e-mail (equal to username())
• userid (equal to userprincipalname())
• brand

I also have a fact table, which contains plenty of transactional data. Also contains the brand in a column.

I created a many-to-many relationship via the brand fiel between the brand_user_addignment table and the fact table. The filter is a one-directional: brand assignment filters the fact table. 

I created a row level security on the brand assignment table for power bi desktop testing purposes (RLS_desktop): [email] = username() // this works fine in desktop.

But the final rls rule, which I created for BI service is not working, does not filter. (This is RLS_service - filters also the brand_assignment talbe): [userid] = userprincipalname().

I also created a measure, to show the userprincipalname() in the power bi service, and it shows the correct userid, for which I want to make the filtering. 

I also added the user to the rls in the power bi service at the dataset's security menu.

Do you have any idea what am I doing wrong?

I did researches, I found posts that the actual user name in the service might not match the userprincipalname? Or is there any mistake I have done?

Thx!

David