Check if your site's DNS is blocked by govt censorship
 

https://asm.ca.com/en/ping.php

This is a site which lets you ping from 90+ locations around the world, but since they show the IP that is resolved for each location, a nice side effect is that you can see if a site is censored by DNS hijacking.

For example, porntube.com has the IP 104.18.147.225 for the large majority of results, but these differ:

China - Hangzhou (cnhgh01) 69.171.244.15
China - Beijing (cnbjs02) 69.63.184.142
Indonesia - Jakarta (idjkt02) 1.2.3.4

I checked a couple of my sites and they're blocked.

That is an interesting site. Thanks for posting. Looks like almost every remotely adult site I can think of is blocked in those 3 spots.

A few sites come up as blocked everywhere though. I wonder if that is maybe a robots.txt setting. Not sure what would cause that appearance. What do you think?

DNS is used before any connection protocol such as HTTP (which is used to fetch robots.txt)

If the IP shows the same for all 90+ sites it suggests there's something wrong with the DNS server for that domain, rather than regional censorship. Can you give me an example hostname?

Edit: if you mean 100% packet loss, it could just be that the webhost's firewall blocks pings.