Cannot Sort Range VBA - "Unable to get sort property of range class"

I am trying to sort a range in VBA and have tried numerous ways of identifying the range without success. I can't figure out why I get the run-time error on the sortfields.clear line (also when I inactivate this line I get the same error on the next line)

Sub Lease_Options()
    
    Dim LastOptionRange As String
   
   
    Range("A4").Select

    ActiveCell.End(xlToRight).End(xlDown).Select
    LastOptionRange = ActiveCell.Address(1, 1)
    

     Range("$A$4:" & LastOptionRange).Sort.SortFields.Clear
    Range("$A$4:" & LastOptionRange).Sort.SortFields.Add _
        Key:=Range("C5", Range("C5").End(xlDown)), SortOn:=xlSortOnValues, Order:=xlAscending, _
        DataOption:=xlSortNormal
    
   
    With Range("$A$4:" & LastOptionRange).Sort
        .Header = xlYes
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With

End Sub

ah that was it. thx!