Access from one country blocked

My clients reported that they cant access to my site from Iran; (They see my site title on browser title bar, but the screen is blank white)
When I pause my site in Cloudflare they have access my site without any problem.
I never added Iran to my firewall; What’s wrong?

I’ve some sites blocked in Iran because they’re served over HTTPS. I can’t recall if it was a .ir or a .com, but it looked like an Iranian ISP issue.

A forum search here for “Iran” should turn up more information.