How do I fix this SlicerCache object error?

Error 424 - "Object required" on the "If Not" line.

I've tried to read up on this error but I am not familiar enough with the SlicerCache to figure this one out - can anyone assist please?

Dim dStartDate As Date
Dim dEndDate As Date
Dim sDateRange As String
Dim sDateRange_Num As String
Dim sDateRangeHeader As String

If Not ActiveWorbook.SlicerCaches("NativeTimeline_Date").FilterCleared = False Then
    dStartDate = ActiveWorkbook.SlicerCaches("NativeTimeline_Date").TimelineState.FilterValue1
    dEndDate = ActiveWorkbook.SlicerCaches("NativeTimeline_Date").TimelineState.FilterValue2

    sDateRange = dStartDate & " - " & dEndDate
    sDateRangeHeader = "Reporting Period: " & sDateRange & " (" & dEndDate - dStartDate & " Days)"
    sDateRange_Num = dEndDate - dStartDate

Else
    dStartDate = WorksheetFunction.Min(Range("D1:D100"))
    dEndDate = WorksheetFunction.Max(Range("D1:D100"))

    sDateRange = dStartDate & " - " & dEndDate
    sDateRangeHeader = "Reporting Period: " & sDateRange & " (" & dEndDate - dStartDate & " Days)"
    sDateRange_Num = dEndDate - dStartDate

End If