Problem publish - Login failed for user

I need help! I am publish project ASP.NET 5 MVC 6 in IIS 8.5 Windows 2012 r2. Configured as https://docs.asp.net/en/latest/publishing/iis.html

But so error - A database operation failed while processing the request. SqlException: Cannot open database "kfliga_KareliaKem" requested by the login. The login failed. Login failed for user 'NT AUTHORITY\SYSTEM'. User'NT AUTHORITY\SYSTEM' configured in SQL Server Management:

1. Server Roles checked public and sysadmin

2. User maping checked kfliga_KareliaKem, db_owner and public

Connection string in appsettings.config -

{"KareliaKemConnection": {"ConnectionString": "Server=(localdb)\\mssqllocaldb; Database=kfliga_KareliaKem;Trusted_Connection=true;MultipleActiveResultSets=true"
    }
  },"Logging": {"IncludeScopes": false,"LogLevel": {"Default": "Verbose","System": "Information","Microsoft": "Information"
    }
  }
}

Thanks in advance!