Siri will not recognise my WhatsApp contacts

Hi up until very recently I have had no issues with either Siri or WhatsApp but I have now noticed an issue.... When I say Hey Siri, WhatsApp message "Any contact" it replies with, "mmmm it looks like "Any contact" doesn't have WhatApp enabled" Obviously I know that these people do have it. My wife is alos having similar issues on hers, anyone else or can anyone suggest a fix?

Many thanks.

[Re-Titled by Moderator]