Hi jjamall ,
Can you share more details on what do you mean from outside , like it is a Public IP or NAT IP for your VIP , please share more details as the information given in your request is not sufficient to understand your issue.
Are you able to access the site from internal network, but not from external or outside network, please share more details.
You can refer the following article on F5 site to perform two-way or mutual Secure Sockets Layer (SSL) authentication.
K12140946: Configuring the BIG-IP system to perform two-way SSL authentication
Configuring the BIG-IP system to perform two-way SSL authentication (f5.com)