After updating the SSL certificates on the local VIP Enterprise Gateway server, external access is still using the old SSL certificate; internal (local LAN) connections are working correctly with the new SSL certificate
External access is going through a F5 (or other) load balancer to facilitate access to the local VIP Enterprise Gateway Self Service Portal service
The load balancer also needs to update the SSL certificate
How to Create, Install, and Manage SSL Certificates on the Symantec VIP Enterprise Gateway: https://knowledge.broadcom.com/external/article/150739/create-install-and-manage-ssl-certificat.html