System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.Data.DuplicateNameException: A column named 'dsFeatures' already belongs to this DataTable. at System.Data.DataColumnCollection.RegisterColumnName(String name, DataColumn column, DataTable table) at System.Data.DataColumnCollection.BaseAdd(DataColumn column) at System.Data.DataColumnCollection.AddAt(Int32 index, DataColumn column) at System.Data.DataColumnCollection.Add(String columnName, Type type) at ISSN_WS1.ISSNws1.ISSN_getFacilityUnitTypes2(String sUserLogin, String sUserPassword, String sFacilityId, String sGroup, String sF1, String sF2) at ISSN_WS1.ISSNws1.ISSN_getFacilityUnitTypes(String sUserLogin, String sUserPassword, String sFacilityId) --- End of inner exception stack trace ---