Pivot Table - unable to set visible property?

I am trying to write code that will display data for the appropriate month selected by the user. I have attached a sample file that has the following error:
"Unable to set the visible property of the pivot item class."
Thank You in advance

Change your OK button code to this:

Private Sub OKButton_Click()
    Dim pt As PivotTable, pi As PivotItem
    Dim DateChosen As String
    
    Application.ScreenUpdating = False
    
    Set pt = Sheets("Pivot").PivotTables("ChannelSummary")
    DateChosen = ListBox1.Value
    
    With pt
        .ManualUpdate = True
        .PivotFields("Month").PivotItems(DateChosen).Visible = True
        For Each pi In .PivotFields("Month").PivotItems
            If pi.Name <> DateChosen Then pi.Visible = False
        Next pi
        .ManualUpdate = False
    End With
    
    Unload Me
End Sub