Adomd connection to cube via http doesn't work after restarting the machine

Question

I've the following code. It's pretty simple. First connect to ssas via http and than get the cube list. It works good until i restart my machine. After restart i get a strange exception (UnknownadomdException) like : incorect data format, and of course i have not the cube list at the end.

But, when after restart i run the Excel i'm able to connect to my ssas with the same connection parameters. After this i can also connect to my ssas in my code.

Do u have any idea?

           List<string> cubeList = new List<string>();

           using (AdomdConnection conn = new AdomdConnection(@"Provider=MSOLAP.4;Persist Security Info=True;User ID=domain.local\userolap;Password=pass;Initial Catalog=ssas;Data Source=http://ssas-server.pl/directory/msmdpump.dll; MDX Compatibility=1;Safety Options=2;MDX Missing Member Mode=Error"))
            {
                try
                {
                    conn.Open();
                    foreach (var cube in conn.Cubes)
                    {
                        if (cube.Name.StartsWith("$")) continue;
                        cubeList.Add(cube.Name);
                    }
                }catch (AdomdException exc)
                {
                    MessageBox.Show(exc.Message);
                }
        }
    }

Thank you for your time.