public void IsConnectAvailiable(string host, string login, string password)
{
    rdc.OnLoginComplete += rdc_OnLoginComplete;
    timer1.Interval = 10000;
    rdc.Server = host;
    rdc.UserName = login;
    rdc.AdvancedSettings8.EnableCredSspSupport = true;
    IMsTscNonScriptable secured = (IMsTscNonScriptable)rdc.GetOcx();
    secured.ClearTextPassword = password;
    rdc.Connect();


}

var staScheduler = new StaTaskScheduler(numberOfThreads: 1);
Task.Factory.StartNew(() =>
    {
        // код
    },
    CancellationToken.None,
    TaskCreationOptions.None,
    staScheduler);