RLS can't work with GROUP name with custom extension

Hi All,

We are using custom security extension for PBIRS site authentication due to third-party SSO integration.

Before customized, RLS works with adding a role and grant 'everyone' to the role.

Currently, with custom extension 'Everyone' can not be added, we created a custom groups so that everyone can access the site, but at RLS permission control page, it only works if we add username one by one. If we add custom groups or 'everyone', people in the custom groups will NOT be able to access the report.

Error Message:

2019-10-08 23:04:47.4770|ERROR|30|GetDataSource ERROR for catalogItem=1df3630b-2a88-473b-9468-54f8b4057260, Exception=Exception of type 'Microsoft.PowerBI.ReportServer.WebApi.ASConnection.RlsNotAuthorizedForModelException' was thrown., ElapsedMs=604| RequestID = 5b415256-3081-d50d-d247-de437388ce13 ClientSessionID = 1fe00b23-32f9-22e4-424b-ef46f63b76a3

2019-10-08 23:04:47.4790|INFO|28|Sending response. Response code [MYID] 401, Elapsed time 0:00:00.6377874| RequestID = 5b415256-3081-d50d-d247-de437388ce13 ClientSessionID = 1fe00b23-32f9-22e4-424b-ef46f63b76a3

My PBIRS version is: 15.0.1102.371

Please advice how can I enable group RLS or grant everyone?

Thanks for any feedback!