Assuming that the temporary page on the website will not contain any product claims, images, or links to other content or websites, and the content will be restricted to a message about the temporary suspension of the site, then there doesn’t appear to be a reason to submit this page to PAAB for review. However, if you are unsure, the temporary page can be submitted to PAAB as an opinion file.
*One additional consideration is if this site is being used as a link to satisfy content requirements from any other pieces in circulation (i.e. safety information, study parameters, reference lists). (see guidance document: Fair Balance & Web Link Destination Examples – Section: Using middle level to lead to highest level fair balance and section 4.4 of the PAAB code). If this is the case, then disabling the website would cause the other circulating pieces to contravene the code.