I am not sure I understand what you are saying. It sounds as if your IIS process cannot log to your MSSQL server through windows authentication. This happens often because the account under which IIS works doesn't have the required access to MSSQL. Check this thread: MS SQL Server with Windows Authentication
Yes, that's right, that's the problem, we would have liked to have authenticated further from the app (radzen) to iss and to the database with the user who is on. But I there are not many who do it. We thought you might have a smart solution to that. but it is not quite easy double hub, Kerberos there is a hell. but thanks anyway