Error on If statement

Hi,
I have a code that aims to comment based on the date values found on column N. However I seem to be encoutering an error with the code when it hits

 S_heet.Select

below is my full code

Public Sub ME_comment()
Dim c_ell As Range, Date_Ref As Date, S_heet As Worksheet
Date_Ref = InputBox("Enter a reference date", "DATE ENTRY", 200, 200)
For Each S_heet In ActiveWorkbook.Sheets
If S_heet.Name <> "Cash Summary" Then
 S_heet.Select
    
    For Each c_ell In Range("N23", Cells(Rows.Count, 23).End(xlUp))
        If IsDate(c_ell) Then
            If c_ell <= Date_Ref Then
                c_ell.Offset(0, -12) = "ME related"
            End If
        End If
    Next c_ell
End If
Next S_heet
End Sub