条件格式运行时错误“ 9”下标超出范围

Question

我正在尝试在VBA Excel中创建宏以应用一些条件格式。

参见下文：

Private Sub CommandButton1_Click()

'Delete conditional formats
    Sheets("Results").Cells.FormatConditions.Delete
'Red formats
    Sheets("Results").Select
    With ActiveSheet.Range("C:C,A:A")
    .FormatConditions.AddUniqueValues
    .FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
    .FormatConditions(1).DupeUnique = xlDuplicate
    End With
    With Selection.FormatConditions(1).Font
        .Color = -16383844
        .TintAndShade = 0
    End With
    With Selection.FormatConditions(1).Interior
        .PatternColorIndex = xlAutomatic
        .Color = 13551615
        .TintAndShade = 0
    End With
    Selection.FormatConditions(1).StopIfTrue = False

'Blue formats
    With ActiveSheet.Range("E:E,C:C,A:A")
    .FormatConditions.AddUniqueValues
    .FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
    .FormatConditions(1).DupeUnique = xlUnique
    End With
    With Selection.FormatConditions(1).Interior
    .PatternColorIndex = xlAutomatic
    .Color = 15773696
    .TintAndShade = 0
    End With

    Selection.FormatConditions(1).StopIfTrue = False
End Sub

错误在以下代码行中弹出：

.FormatConditions(Selection.FormatConditions.Count).SetFirstPriority

有时有时无法正常工作。

我录制了这个宏，几天前运行良好。