SSL deep inspection break Instagram.com

Hi,

I have on fortigate ssl deep inspection configured, certificate is installed on every client pc and this is working. 

Now I have problem when accessing instagram.com page and I found using trial and error method disabling one by one security profiles that this page is not working because of deep ssl inspection, when disabled I have access to instagram.com

My question is how could I troubleshoot problems with ssl inspections like this one, because if I go to Log & Report --- > SSL then everytime logs here are empty?