Manage security and RLS with custom authentication

Hello everybody,

I am a bit new in Power BI Report Server. I installed my evaluation trial and configured with reports and Windows users fine. Then I needed to use custom authentication, so I tried to get it as explained in https://github.com/Microsoft/Reporting-Services/tree/master/CustomSecuritySample#start-of-content and in the end it worked fine.

I created clicking on "Register new user" of login window, then I added it in Security element in RSReportServer.config file (step 3 of the article) and finally I could login. When I am in the Report Server, I see reports, I can manage security on first page and choosing Element roles and System roles, but a lot of things are not working as it always tells me "An error occurred. Try later":

• I can't open the Menu of any report, where I could manage RLS, updates, title and so on clicking on right-upper corner 
• I can't open any report
• I can manage Element and Security roles but they look not to work as I gave me Content Manager and System Administrator but I can't edit anything about reports.

I don't see previous domain users anymore but maybe it's normal, but I need to configure many users and giving them permissions about folders and reports but it doesn't work.

Some particular aspects which could be useful:

• In Report Server Configuration Manager, as Service Account I use a domain account of my server which I used before to login to Report Server too, maybe I should change? I don't know but I don't think
• In step 4 of the article to configure custom authentication you need to generate machine key with Validation="AES" but when I generated it with my server I got Validation="HMACSHA256"

Please help me because I really need to configure it in the right way, it's very important to me.

Thanks a lot

Nick