Apache + SSL + Varnish.
For each separate browser Varnish create a different version of each page. So each new user is visiting slow version until he visit the same page in the same browser.
Workaround was to disable Vary cookie and cache of static content in which the cookies are included too. No luck till now.
This is because of your backend is not sending User-Agent HTTP header so i think you should check this for more information you can check varnish-cache-cache-only-seems-warmed-on-each-browser this.
Hope this answer help.
if above answer was helpful then please Accept as Solution & give KudosShubham Khandelwal
Hi @shubham_khandelwal1 ,
Thanks for your suggestion but as I can see my backend is sending the User-Agent HTTP header or I'm wrong.