It too me a while to work out why my Nextcloud stuff wasn’t working on my phone. It wasn’t until I went to http://duckdns.org on mobile data I saw the block. I had changed ISP from one with IPv6, which I had setup, to an ISP without it, and thought it might be that. But it was just coincidence.
I’ve written to O2 but I doubt they will change anything, so I’ll be changing network.
So heads up UK O2 self hosting people!
What is their reasoning?
Save the children
Piracy concerns
Laws
Someone didnt get paid.
Pick at least one.
In all seriousness: I don’t know.
Lots of malware gets hosted using dynamic DNS domains, so they (or more likely some bot) probably saw the domain frequently showing up in malicious activity and blocked it without understanding that it itself isn’t the source of the malicious activity.
“This page has been blocked for either a legal or technical reason.”
But you can see the block page used yourself at: http://shieldcf.o2.co.uk/blacklist