VBA stopped working!!

Yesterday I received great help from everyone on the code below. It worked perfectly allowing me to select more than one item in a drop down.

Today it stopped working. I had copied the file with a new name and changed the target column to 14 (Column N) and it did not work.

I went back to the original file with column 10 and it does not work either. Any ideas would be appreciated.....thanks again Max
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Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim sOld    As String
    Dim sNew    As String
    Dim rVal    As Range

    If Target.Column <> 14 Then Exit Sub


    On Error Resume Next
    Set rVal = Me.Cells.SpecialCells(xlCellTypeAllValidation)
    If rVal Is Nothing Then Exit Sub
    On Error GoTo 0

    If Not Intersect(Target, rVal) Is Nothing Then
        Application.EnableEvents = False
        sNew = Target.Value
        Application.Undo
        sOld = Target.Value

        If Len(sNew) = 0 Then
            Target.ClearContents
        ElseIf Len(sOld) = 0 Then
            Target.Value = sNew
        Else
            Target.Value = sOld & ", " & sNew
        End If

        Application.EnableEvents = True
    End If
End Sub