InvalidOperationException-Need-to-add-DateTime-also

System.InvalidOperationException: Need to add DateTime also
at WealthLab.Core.DateSynchedList`1.Add(T value)
at WealthLab.Core.BarHistory.set_ExtendedBars(Int32 value)
at WealthLab.ChartWPF.CoreChart.AssignBars(BarHistory value, Boolean setOffsetZero, Boolean force, Boolean calledFromStreaming)
at WealthLab.ChartWPF.CoreChart.set_Bars(BarHistory value)
at WealthLab.ChartWPF.Chart.InvokeCustomer(Boolean isvalue, DataSet selection)
at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)