What role and acl are those clients using?
Be sure that whatapp use more than only 443. Add all needed ports in your ACL aswell as your external firewall.
https://www.quora.com/What-is-the-port-number-for-whatsapp
Kind Regards Marcel Koedijk
HPE ASE Flexnetwork | ACMP | ACCP - Was this post usefull, Kudos are welcome.
