I recently faced this problem and I’ve been able to solve the issue. My ISP is Vodafone, with Fiber To The Home. It looks like they are a blocking glitch domain on their DNS resolver.
I engaged their technical support and they made me change the DNS settings of the Vodafone Station (previous local tests with dig or changing the network configuration on my computer were not successful). I tested different DNSs (Google, Quad9, Cloudflare) and in all cases I was able to access glitch websites again
The process will probably be dependant on you specific modem but in general you need to edit the DNS settings (Internet > DNS in mine), enable manual configuration and configure IPv4 and IPv6 DNS settings with you desired DNS (I suggest Quad9 but any should work as long as is not blocking glitch.me, which I think may be the case for “secure” or DNS with parental control enabled).
I use Vodafone too but I’ve always been able to access .glitch.me domains without needing to change any settings. (not the new “add external websites to profile” feature tho)
Bumping here. 5 years later, glitch.me is still blocked in Italy. That’s 60M users that can’t use this service. Any updates? Anything we can do to push to unblock?
Someone in Italy sent us info about the action a few years ago so I assume it was public but I don’t have any other info than that. This is not an uncommon issue for hosting companies, from what I’ve been told.