save file with current date

hi, I am trying to do something simple in excel 2013 vba but it's not working. I just want to save a version of the active workbook in the existing subdirectory but with a date stamp at the end of the file name. I am using the code below. appreciate any help.

Sub Save_File_Today_Date()
' save file with today's date
  ActiveWorkbook.SaveAs Format(Now(), “DD - MMM - YY”)

End Sub