ArcGIS Engine访问ArcGISServer服务代码段报错

具体代码段如下，最后一行代码报错
 
            IPropertySet propertySet = new PropertySetClass();
            propertySet.SetProperty("url", "https://myServer:6443/arcgis/rest/services";);
            propertySet.SetProperty("ConnectionMode", esriAGSConnectionMode.esriAGSConnectionModeConsumer);
            propertySet.SetProperty("ServerType", esriAGSServerType.esriAGSServerTypeDiscovery);
            propertySet.SetProperty("user", "arcgis");
            propertySet.SetProperty("password", "arcgis");
            propertySet.SetProperty("ALLOWINSECURETOKENURL", true); 
            IAGSServerConnectionName3 pConnectName = new AGSServerConnectionNameClass() as IAGSServerConnectionName3;
            pConnectName.ConnectionProperties = propertySet;
            IAGSServerConnectionAdmin pAGSAdmin = ((IName)pConnectName).Open() as IAGSServerConnectionAdmin;

            IServerObjectManager som = pAGSAdmin.ServerObjectManager;--此行代码报错，提示信息为 The supplied command does not exist in command pool
不知道是哪里出了问题，有哪位朋友遇到过吗 ！！！